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WORKS  OF 
J.  MERRITT    MATTHEWS 

PUBLISHED    BY 

JOHN  WILEY  &  SONS 


The  Textile  Fibres 

Their  Physical,  Microscopical,  and  Chemical 
Properties.  Third  edition,  rewritten.  8vo,  xi  + 
630  pages,  141  figures.  Cloth,  $4.00  net. 

Laboratory  Manual  of   Dyeing  and  Textile  Chem- 
istry 

8vo,  xii  +  363  pages.     Cloth,  J3.50. 

TRANSLATION 
General  Principles  of  Organic  Syntheses 

By  P.  Alexeyeff,  late  Professor  of  Chemistry, 
University  of  Kieff,  Russia.  Authorized  trans- 
lation, with  Revisions  and  Additions,  by  J.  Mer- 
ritt  Matthews,  Ph.D.  8vo,  viii  +  246  pages. 
Cloth,  $3.00. 


THE  TEXTILE  FIBRES 

THEIR   PHYSICAL,    MICROSCOPICAL 

AND 

CHEMICAL   PROPERTIES 


BY 

J.   MERRITT  MATTHEWS,  PH.D. 

Formerly  Head  of  Chemical  and  Dveing  Department  Philadelphia    Textile   School 
Consulting   Chemist  to  the    Textile  Industries. 


THIRD  EDITION,  REWRITTEN 

FIRST    THOUSAND 


NEW  YORK 

JOHN    WILEY     &    SONS 

LONDON:   CHAPMAN  &  HALL,    LIMITED 

1913 


COPYRIGHT  1904,  .1907,   1913 

BY 
J.    MERRITT    MATTHEWS 


THE   SCIENTIFIC   PRESS 

ROBERT   DRUMMOND    AND  COMPANY 

BROOKLYN,  N.   Y. 


PREFACE 


THE  present^book,  it  is  hoped,  will  be  of  assistance  to  both 
the  practical  operator  in  textiles  and  the  student  of  textile 
subjects.  It  has  been  the  outgrowth  of  a  number  of  years  of 
experience  both  in  the  teaching  of  textile  chemistry  and  in  the 
practical  observation  in  the  many  mill  problems  which  have  come 
under  the  notice  of  the  author  in  the  practice  of  his  profession. 

The  textile  fibres  form  the  raw  materials  for  many  of  our 
greatest  industries,  and  hence  it  is  of  importance  that  the  facts 
concerning  them  should  be  systematized  into  some  form  of 
scientific  knowledge.  The  author  has  attempted,  however,  not 
to  allow  the  purely  scientific  phase  of  the  subject  to  overbalance 
the  practical  bearing  of  such  knowledge  on  the  every-day  prob- 
lems of  industry. 

Heretofore,  the  literature  on  the  textile  fibres  has  been  chiefly 
confined  to  a  chapter  or  two  in  general  treatises  on  dyeing  or 
other  textile  subjects,  or  to  specialized  books  such  as  those  of 
Hohnel,  Hanausek  and  Wiesner  on  the  microscopy  of  the  fibres. 
It  has  been  the  author's  endeavor,  in  the  present  volume,  to 
bring  together,  as  far  as  possible,  all  of  the  material  available 
for  the  study  of  the  textile  fibres.  Such  material  is  as  yet 
incomplete  and  rather  poorly  organized  at  its  best;  but  it  is 
hoped  that  this  volume  may  prove  a  stimulus  along  the  several 
lines  of  research  which  are  available  in  this  field.  Unfortunately, 
the  subject  of  the  textile  fibres  has  been  lamentably  neglected 
by  chemists,  although  there  is  abundant  indication  that  a  fertile 
field  of  research  is  open  to  chemists  in  this  direction,  and  such 
work  would  have  not  only  a  scientific  value,  but  would  also  be 
of  great  industrial  worth.  There  is,  as  yet,  relatively  little 

ill 
• 

261189 


iv  PREFACE 

known  concerning  the  chemical  constituents  of  the  fibres,  and 
the  manner  in  which  the  varying  chemical  conditions  of  bleach- 
ing and  dyeing  and  other  chemical  treatments,  affect  the  com- 
position and  properties  of  these  constituents.  The  action  of 
various  chemical  agents  on  the  fibre  as  an  individual  has 
been  but  very  imperfectly  studied.  More  work  has  been  done 
in  the  microscopical  field  concerning  the  properties  of  the 
fibres;  but  even  here  the  knowledge  is  very  incomplete  and 
disjointed,  and  especial  attention  is  drawn  to  the  fact  that 
there  is  yet  a  large  amount  of  work  to  be  done  in  the  micro- 
chemistry  of  the  subject. 

The  author  has  endeavored  to  emphasize  throughout  this 
volume  the  importance  of  the  study  of  the  fibre  as  an  individual, 
for  in  many  cases  it  is  misleading  to  assume  that  the  behavior 
of  the  individual  fibre  is  identical  with  that  of  a  large  mass  of 
fibres  in  the  form  of  yarn  or  cloth.  In  the  latter  case,  the  dif- 
ference in  physical  condition  and  the  action  of  mechanical  forces 
have  an  important  influence.  By  going  back  to  the  study  of 
the  individual  fibre  as  a  basis,  many  explanations  can  be  given 
which  could  not  otherwise  be  discovered. 

It  is  hoped  that  this  book  may  afford  instruction  both  to 
the  manufacturer  and  to  the  student;  assisting  the  former  in 
solving  some  of  the  many  practical  problems  constantly  occurring 
in  the  manufacture  of  textiles,  and  urging  the  latter  on  to  an 
increased  effort  in  the  scientific  development  of  the  subject. 

J.  MERRITT  MATTHEWS. 

50  EAST  4iST  STREET,  NEW  YORK, 
January,  1913. 


CONTENTS 


CHAPTER  I 

CLASSIFICATION   OF   THE   TEXTILE   FIBRES 

PAGE 

1.  Fibres  Chiefly  Used  for  Textiles i 

2.  Properties  Required  in  a  Textile  Fibre i 

3.  Animal  and  Vegetable  Fibre 6 

4.  Mineral  Fibres;  Asbestos o 


CHAPTER  II 

WOOL   AND   HAIR   FIBRES 

1.  The  Sheep 14 

2.  Classification  of  Fibres  in  Fleece 17 

3.  Physiology  and  Structure  of  Wool 26 

v  Microscopy  of  Wool 31 

5.  The  Epidermal  Scales 36 

6.  The  Cortical  Cells 38 

7.  The  Medullary  Cells 40 

8.  Physical  Properties 43 

9.  Conditions  Affecting  Quality  of  Wool 46 


CHAPTER  III 

THE   CHEMICAL   NATURE   AND   PROPERTIES   OF    WOOL   AND   HAIR   FIBRES 

1.  Composition  of  Raw  Wool 49 

2.  Wool  Grease;  Cholesterol 50 

3-  Suint :  .  . .  51 

4.  Ash  of  Wool  Fibre ."... 51 

5.  Coloring  Matter 52 

6.  Chemical  Constitution  of  Wool;  Keratin 53 


vi  CONTENTS 

PAGE 

7.  Nitrogen  in  Wool;  Lanuginic  Acid 55 

8.  Sulphur  in  Wool 57 

9.  Chemical  Reactions  of  Wool;  with  Water 59 

10.  Acid  and  Basic  Nature  of  Wool 60 

11.  Action  of  Acids  on  Wool 61 

12.  Action  of  Alkalies  on  Wool 65 

13.  Action  of  Oxidizing  Agents  on  Wool 67 

14.  Action  of  Chlorin  on  Wool 69 

15.  Action  of  Metallic  Salts;  Mordants 70 

16.  Action  of  Dyestuffs  on  Wool 72 

17.  Mildew  on  Wool 74 

18.  Microchemical  Reactions 75 

19.  Hygroscopic  Quality 75 


CHAPTER  IV 

SHODDY  AND   WOOL  SUBSTITUTES 

1 .  Varieties  of  Shoddy 79 

2.  Examination  of  Shoddy 81 


CHAPTER  V 

MINOR   HAIR   FIBRES 

1.  The  Minor  Hair  Fibres 85 

2.  Mohair 85 

3.  Cashmere 88 

4.  Goat-hair 88 

5.  Alpaca 91 

6.  Vicuna  Wool 94 

7.  Llama  Fibre 95 

8.  Camel-hair 96 

9.  Cow-hair 99 

10.  Minor  Hair  Fibres . .                                                                                    .  101 


CHAPTER  VI 

SILK;  ITS  ORIGIN  AND  CULTIVATION 

1.  General  Considerations 105 

2.  The  Silkworm 105 

3.  The  Cocoon in 

4.  Diseases  of  the  Silkworm 114 

5.  Wild  Silks .  116 


CONTENTS  vii 


CHAPTER  VII 


PHYSICAL   PROPERTIES   OF   SILK 

PAGE 

1.  The  Microscopy  of  the  Silk  Fibre 1 20 

2.  Physical  Properties  of  Silk 123 

3.  Silk-reeling 127 


CHAPTER  VIII 

CHEMICAL   NATURE   AND   PROPERTIES   OF   SILK 

1.  Chemical  Constitution 131 

2.  Fibroin 133 

3.  Sericin ". 138 

4.  Coloring  Matter 140 

5.  Chemical  Reactions 141 

6.  Tussah  Silk 147 

7.  Byssus  Silk : 150 


CHAPTER  IX 

THE   VEGETABLE   FIBRES 

1.  General  Considerations 152 

2.  Classification 157 

3.  Physical  Structure 168 

4.  Physical  Properties 172 

5.  Chemical  Composition  and  Properties 174 

6.  Lignin 177 

7.  Chemical  Investigation  of  Vegetable  Fibres 180 


CHAPTER  X 

COTTON 

1 .  Historical 184 

2.  Origin  and  Growth 188 

3.  Varieties  of  Cotton 205 

4.  Grading  of  Cotton 224 


vin  CONTENTS 

CHAPTER  XI 

THE   PHYSICAL   STRUCTURE   AND   PROPERTIES   OF   COTTON 

PAGE 

1.  Physical  Structure  ........................  .........................  227 

2.  Dimensions  of  Cotton  Fibres  ........................................  229 

3.  Anatomical  Structure  ..............................................  241 

4.  Microscopy  of  Cotton  Fibre  .........................................  245 

•5..  Physical  Properties,  Spinning  Qualities  ...............................  250 

6.  Tensile  Strength  ..............................................  .....  250 

7.  Method  of  Determining  Tensile  Strength  of  Fibres  .....................  253, 

8.  Hygroscopic  Quality  .........  255 


CHAPTER   XII 

CHEMICAL   PROPERTIES    OF    COTTON;    CELLULOSE 

1.  Chemical  Constitution  ...........................................  260 

2.  Impurities  in  Cotton  ..............................................  260 

3.  Cellulose  .......................................................  268 

4.  Chemical  Reaction  of  Cotton;  Heat  ................................  282 

5.  Action  of  Water  ..................................................  284 

6.  Action  of  Cuprammonium  Solution  .................................  284 

7.  Action  of  Zinc  Chloride  .......................................  .....  285 

8.  Action  of  Acids  ...................................................  288 

9.  Hydrocellulose  .............................  ......................  289 

10.  Action  of  Nitric  Acid  ..............................................  288 

1  1  .  Action  of  Organic  Acids  ...........................................  294 

1  2.  Action  of  Tannins  ....  ........................  ....................  295 

13.  Action  of  Alkalies  .................................................  298 

14.  Action  of  Oxidizing  Agents;  Oxycellulose  ............................  298 

15.  Action  of  Metallic  Salts  .............................  ..............  303 

16.  Flame-proofing  of  Cotton  Fabrics  ..................................  304 

17.  Action  of  Coloring  Matters  ........................................  305 

18.  Action  of  Ferments  ...............................................  306 


CHAPTER  XIII 

MERCERIZED   COTTON 

1 .  Mercerizing 308 

2.  Alkali-cellulose 3°9 

3.  Changes  in  Cotton  Fibre  by  Mercerizing 312 


CONTENTS  ix 


4.  Conditions  of  Mercerizing;  Chemicals  Employed 318 

5.  Temperature  of  Mercerizing 320 

6.  Time  of  Mercerizing • 323 

7.  Tension  in  Mercerizing 324 

8.  Washing  as  a  Process  in  Mercerizing 326 

9.  Quality  of  Fibre  for  Mercerizing 327 

10.  Methods  of  Mercerizing 330 

11.  Recovery  of  Caustic  Soda  from  Mercerizing  Liquors 332 

12.  Properties  of  Mercerized  Cotton 333 

13.  Cellulose  Hydrate;  Hydracellulose 339 

14.  Microscopy  of  Mercerized  Cotton 341 

15.  Schreiner  Finish 342 


CHAPTER  XIV 

THE   MINOR   SEED-HAIRS 

1 .  Bombax  Cotton 343 

2.  Kapok 345 

3.  Vegetable  Silk 347 


CHAPTER  XV 

ARTIFICIAL   SILKS 

1.  General  Considerations 351 

2.  Collodion  or  Chardonnet  Silk 353 

3.  Lehner's  Silk 359 

4.  Other  Collodion  Silks 359 

5.  Cuprammonium  Silk 360 

6.  Use  of  Other  Cellulose  Solutions 364 

7.  Viscose  Silk 364 

8.  Acetate  Silk , , 370 

9.  Gelatin  Silk .  .  . 372 

10.  Other  Uses  of  Cellulose  Solutions 373 

11.  Properties  of  Artificial  Silk 373 

12.  Comparison  of  Artificial  Silks 377 

13.  Animalized  Cotton 381 


CHAPTER  XVI 

LINEN 

1 .  Preparation 382 

2.  Chemical  and  Physical  Properties 392 


x  CONTENTS 

CHAPTER  XVII 

JUTE,   RAMIE,   HEMP,   AND  MINOR  VEGETABLE   FIBRES 

PAGE 

i-  Jute-  •  399 

2.  Lignocellulose 407 

3.  Ramie  or  China  Grass 410 

4-  Hemp 4I6 

5.  Sunn  Hemp 425 

6.  Ambari  or  Gambo  Hemp 429 

7.  New  Zealand  Flax 430 

8.  Manila  Hemp 435 

Q.  Sisal  Hemp 439 

10.  Aloe  Fibre  or  Mauritius  Hemp 443 

11.  Pita  Fibre 444 

12.  Pineapple  Fibre  of  Silk  Grass 446 

13.  Coir  Fibre 447 

14.  Istle  Fibre 450 

15.  Nettle  Fibre 451 

16.  Fibre  of  Urena  Sinuata 452 

1 7.  Sansevieria  Fibres 452 

18.  Tillandsia  Fibre 454 

IQ.  Fibre  of  Sea  Grass 454 

20.  Raphia " 454 

21.  Bromelia  Fibres 455 

22.  Piassava 458 

23.  Textile  Yarns  from  Wood-pulp 459 

CHAPTER  XVIII 

ANALYSIS   OF   THE   TEXTILE   FIBRES 

1.  General  Considerations 461 

2.  Qualitative  Tests 462 

3.  Distinction  between  Animal  and  Vegetable  Fibres 466 

4.  Analytical  Reactions  of  Vegetable  Fibres 471 

5.  Distinction  between  Cotton  and  Linen 473 

6.  Distinction  between  New  Zealand  Flax,  Jute,  Hemp,  and  Linen 476 

7.  Distinction  between  Manila  Hemp  and  Sisal 478 

8.  Ligneous  Matter 478 

9.  Reactions  of  Bast  Fibres 478 

10.  Systematic  Analysis  of  Mixed  Fibres 481 

n.  Detection  of  Cotton  in  Kapok 481 

12.  Microscopical  Comparison  of  Various  Fibres 483 

13.  Identification  of  Artificial  Silks 483 

14.  Distinction  between  True  Silk  and  Different  Varieties  of  Wild  Silk 488 


CONTENTS  xi 

PAGE 

15.  Micro-analytical  Tables  for  Vegetable  Fibres 494 

16.  Analysis  of  Bleached  Cotton 512 


CHAPTER  XIX 

ANALYSIS   OF   TEXTILE   FABRICS   AND   YARNS 

1.  Wool  and  Cotton  Fabrics 517 

2.  Wool  and  Silk •. 522 

3.  Silk  and  Cotton 523 

4.  Wool,  Silk,  and  Cotton 524 

5.  Conditioning  of  Textiles 532 

6.  Calculations  Involved  in  Conditioning 539 

7.  Analysis  of  Weighting  in  Silk  Fabrics 551 

8.  Oil  and  Grease  in  Yarns  and  Fabrics 568 

9.  Estimation  of  Finishing  Materials  on  Fabrics 570 

10.  Testing  the  Waterproof  Quality  of  Fabrics 570 

11.  Testing  the  Liability  of  Waterproofed  Fabrics  to  Spontaneous  Com- 

bustion    573 

12.  Microscopic  Analysis  of  Fabrics 574 

13.  Determination  of  the  Size  of  Yarns 577 

BIBLIOGRAPHY  OF  THE  TEXTILE  FIBRES 593 


THE  TEXTILE  FIBRES 


CHAPTER  I 

CLASSIFICATION  OF  THE  TEXTILE  FIBRES 

1.  Fibres  Chiefly  Used  for  Textiles. — In    order  to  be  ser- 
viceable in  a  textile  fabric,  a  fibre  must  possess  sufficient  length 
to  be  woven  and  a  physical    structure  which  will  permit  of 
several   fibres  being   spun   together,    thereby   yielding   a   con- 
tinuous thread  of  considerable  tensile  strength  and  pliability. 
Although  there  are  several  fibres,  such  as  spun  glass,  asbestos, 
various  grasses,  etc.,  which  are  used  for  the  manufacture  of 
textiles  in  peculiar  and  rare  instances,  yet  the  fibres  which 
are  employed  to  the  greatest  extent  and  which  exhibit  the  most 
satisfactory  qualities  are  wool,  silk,  cotton,  and  linen.     All  of 
these  possess   an  organized   structure,   and   are   the  products 
of  a  natural  growth  in  life  processes. 

2.  Properties  Required  in  a  Textile  Fibre. — The  availability 
of  a  fibre  for  textile  purposes  must  be  considered  with  reference 
to  its   adaptation    to   the    various    operations    and   processes 
through   which   it   is    required    to    pass  in   the   formation   of 
a   woven   fabric.     Preliminary   to    the   operation   of    weaving 
(or  other  similar  operation  by  which  a  fabric  is   made)  it  is 
necessary    that    a    continuous    thread    or    yarn    be    prepared 
from  the  fibre,  and  for  the  manufacture  of  such  a  yam  certain 
qualities  are  necessary  and  certain  others  are  desirable.     Prob- 
ably the  most  important  quality  in  this  connection  is  tensile 
strength  for  if  the  individual  fibre  does  not  possess  in  itself 
considerable  strength  it   will  not  be  possible   to  make  from 


2  THE  TEXTILE   FIBRES 

it  a  yarn  suitable  for  use  in  the  arts.  There  are  a  number  of 
fibres,  especially  among  the  vegetable  class  (such  as  those  of 
the  common  milkweed,  etc.),  which  might  prove  of  considerable 
value  but  for  their  lack  of  sufficient  tensile  strength.  The 
four  fibres  mentioned  in  the  preceding  paragraph  as  the  most 
important  are  all  characterized  by  ~a  high  tensile  strength. 
Although  dependent  also  on  other  qualities,  the  resistance  of  a 
fibre  to  use  and  wear  is  primarily  dependent  on  its  tensile 
strength. 

The  second  important  quality  which  determines  the  useful- 
ness of  a  textile  fibre  is  its  length.  It  is,  of  course,  very  easy 
to  understand  without  even  resort  to  technical  explanations, 
that  where  a  continuous  thread  is  to  be  made  up  of  a  large  num- 
ber of  individual  elements,  these  elements  must  possess  a  con- 
siderable length  with  reference  to  their  thickness,  otherwise 
it  would  not  be  possible  to  make  a  thread  that  would  hold 
together.*  In  a  general  way  and  other  conditions  being  equal, 
the  strength  of  such  a  thread  will  be  directly  proportional  to 
the  length  of  the  individual  fibre  elements  employed.  On 
this  account  a  yarn  composed  of  the  long  fibres  of  Sea  Island 
cotton  is  much  stronger  than  a  similar  yarn  prepared  from  the 
relatively  short  fibres  of  upland  cotton. 

A  third  essential  quality  for  a  textile  fibre  is  cohesiveness. 
By  this  is  meant  the  property  of  the  individual  fibres  cohering 
or  holding  on  to  one  another  when  spun  into  a  yarn.  This 
is  usually  brought  about  by  the  surface  of  the  fibres  possessing 
a  high  degree  of  frictional  resistance.  The  surface  of  wool, 
for  instance,  is  quite  rough  and  serrated  by  reason  of  the  pro- 
jecting edges  of  its  epidermal  scales,  the  same  as  the  surface  of 
a  fish.  These  projections  easily  catch  in  one  another,  so  that 
when  several  wool  fibres  are  twisted  together  they  offer  con- 
siderable frictional  resistance  to  being  pulled  apart.  Cotton 
also  possesses  an  irregular  surface  which  manifests  a  high 
degree  of  friction  and  this  is  greatly  accentuated  by  the 

*  The  lowest  economic  limit  in  length  for  fibres  to  be  employed  for  pur- 
poses of  spinning  is  about  5  mm.  Fibres  of  less  length  than  this,  however, 
are  available  for  paper  making. 


CLASSIFICATION   OF  THE  TEXTILE   FIBRES  3 

occurrence  of  many  twists  in  the  fibre  which  interlock  when 
several  fibres  are  spun  together,  and  thus  prevent  the  elements 
of  the  yarn  from  slipping  apart  when  subjected  to  strain.  Linen 
(and  other  analogous  vegetable  fibres)  has  also  a  roughened 
surface,  and  furthermore  possesses  knot-like  formations  through- 
out its  length,  which  of  course,  greatly  enhance  the  surface 
friction  of  the  fibre.  Silk,  on  the  other  hand,  wrhen  con- 
sidered as  the  purified  fibre,  has  a  comparatively  smooth  sur- 
face, and  its  cohesiveness  when  employed  as  a  spun  fibre  as 
in  the  case  of  waste  silk,  is  chiefly  due  to  its  great  length  in 
proportion  to  its  thickness  which  allows  of  the  fibre  elements 
of  the  yarn  wrapping  around  one  another  a  great  number  of 
times,  giving  rise  in  this  manner  to  great  frictional  resistance. 
When  silk  is  not  employed  as  a  spun  fibre,  as  in  the  case  of 
thrown  silk  yarns,  the  individual  elements  of  the  yarn  must 
be  considered  as  practically  continuous  filaments.  The  lack 
of  cohesiveness  in  many  minor  vegetable  fibres  such  as  ramie 
and  the  several  varieties  of  so-called  vegetable  silks,  greatly 
reduces  their  otherwise  practical  value  as  spinning  fibres.  The 
latter  fibres  more  especially  possess  very  smooth  surfaces, 
and  consequently  they  slip  over  one  another  in  a  yarn  and  are 
easily  pulled  apart. 

Another  quality  which  is  very  essential  to  a  satisfactory 
textile  fibre  is  pliability  which  permits  of  one  fibre  being  easily 
wrapped  around  another  in  the  spinning  operation.  The  stiffer 
and  more  wiry  the  nature  of  a  fibre,  the  less  is  it  adapted  to  the 
purposes  of  textile  use.  The  fibres  of  ordinary  wool,  for  instance, 
are  very  pliable,  and  are  employed  in  the  production  of  a  wide 
variety  of  fabrics  for  which  a  stiff  wiry  fibre,  such  as  horse- 
hair, would  be  entirely  unsuitable.  The  pliability  of  a  fibre 
also  determines  in  great  measure  its  elasticity  and  resiliency, 
qualities  which  are  often  of  prime  importance  in  the  manu- 
facture of  textile  fabrics.  Lack  of  these  properties  will  make 
the  fibre  and  its  resulting  products  brittle  and  unyielding, 
and  hence  greatly  limit  the  field  of  its  usefulness.  Fibres 
of  glass,  for  instance,  however  fine  they  may  be  prepared, 
have  a  very  narrow  range  of  utility. 


4  THE  TEXTILE  FIBRES 

Furthermore,  a  fibre  must  possess  sufficient  fineness  of 
staple  to  be  useful  in  the  production  of  spun  yarns.  The 
principal  fibres  all  have  very  small  diameters  and  a  large  number 
of  them  can  be  twisted  together  to  yield  a  fine  thread.  Other 
things  being  equal,  the  finer  the  staple  of  the  fibre,  the  finer 
the  yarn  which  can  be  produced  from  it.  The  coarse  vege- 
table fibres,  such  as  jute,  hemp,  sisal,  etc.,  can  only  be  used  for 
textile  purposes  in  the  production  of  crude,  low-grade  fabrics; 
the  chief  uses  of  such  fibres  being  for  the  manufacture  of  bagging, 
cordage,  etc. 

Besides  these  more  properly  termed  essential  qualities, 
there  are  a  number  of  others  which  more  or  less  determine 
the  value  of  a  fibre  for  textile  purposes.  Uniformity  of  staple 
is  a  valuable  property;  by  this  is  meant  evenness  in  the  length 
and  diameter  of  the  individual  fibres.  This  enhances  the 
spinning  quality  very  much  and  aids  in  the  production  of  an 
even  thread.  If  in  one  variety  of  cotton,  for  instance,  the 
individual  fibres  vary  widely  in  their  length  and  diameter,  its 
value  will  be  much  less  than  another  variety  in  which  these 
dimensions  are  more  uniform.  As  both  wool  and  cotton  in 
their  natural  state  show  considerable  variation  in  the  size  of 
the  individual  fibres,  in  order  to  heighten  the  quality  of  the 
yarns  produced  a  process  known  as  "  combing  "  is  utilized, 
whereby  the  longer  fibres  are  separated  from  the  shorter  ones, 
and  hence  much  greater  uniformity  in  staple  is  obtained.  The 
more  uniform  the  length  of  the  fibres,  the  more  even,  and 
hence  stronger,  will  be  the  resulting  yarn. 

Another  desirable  quality  for  a  textile  fibre  to  possess  is 
that  of  porosity  or  capillarity.  By  this  is  meant  that  the 
fibre  should  be  capable  of  easily  absorbing  liquids  and  solu- 
tions and  of  permitting  these  to  thoroughly  permeate  its  sub- 
stance. This  property  is  important  as  it  allows  of  the  dyeing, 
bleaching,  and  otherwise  preparing  the  fibres  by  modifying  their 
natural  condition.  Fib-res  that  cannot  be  dyed  or  bleached 
would  have  but  a  limited  application  in  the  manufacture  of 
textiles. 

A  further  quality,  which  under  certain  conditions  enhances 


CLASSIFICATION   OF  THE  TEXTILE   FIBRES  5 

the  value  of  a  textile  fibre,  is  lustre.  Fibres  possessing  this 
quality  to  a  marked  degree,  such  as  silk,  mercerized  cotton, 
and  certain  kinds  of  wool,  are  capable  of  producing  a  wide 
variety  of  beautiful  effects.  Lustre,  however,  is  not  an  essential 
quality  in  a  fibre  as  regards  usefulness;  it  is  only  an  ornamental 
quality  which  adds  to  the  beauty  of  the  product. 

There  are  two  other  features  which  must  also  be  con- 
sidered with  reference  to  the  textile  fibres  as  well  as  to  any 
other  manufactured  article.  The  first  of  these  is  durability, 
by  which  is  meant  that  the  substance  of  which  the  fibre  is  com- 
posed must  possess  a  degree  of  permanence  which  permits  of 
its  general  use;  it  must  be  capable  of  withstanding  the  con- 
ditions of  wear  to  which  it  may  be  reasonably  subjected.  The 
use  of  artificial  silk  (lustra-cellulose),  for  instance,  is  greatly 
limited  by  reason  of  the  fact  that  this  fibre  becomes  much  weak- 
ened and  is  liable  to  undergo  disintegration  when  moistened  with 
water.  The  principal  textile  fibres  are  all  very  resistant  to 
the  ordinary  conditions  of  wear,  more  so,  in  fact,  than  many 
of  the  raw  materials  used  in  the  preparation  of  manufactured 
articles.  The  second  feature  to  which  reference  is  made  has 
principally  an  economic  significance.  In  order  to  possess 
commercial  value  a  fibre  must  be  available  in  large  quantity, 
and  its  supply  must  be  more  or  less  constant  and  readily 
marketed;  it  furthermore  must  be  cheap.  It  is  possible  to 
use  spider's  silk,  for  example,  as  a  textile  fibre  for  certain 
purposes,  but  the  supply  of  this  material  is  small  and  uncertain, 
and  there  are  many  difficulties  in  the  way  of  its  production 
which  would  doubtless  prevent  it  ever  becoming  a  staple 
article  of  commerce.  There  are  a  large  number  of  vegetable 
fibres  which  examination  shows  to  possess  many  valuable 
properties  for  textile  purposes,  but  the  practical  supply  of  which 
is  so  uncertain  as  to  render  them  unworthy  of  commercial 
consideration. 

Though  textile  fibres  in  general  consist  of  a  wide  range  of 
materials,  for  convenience  in  study  they  may  be  divided  into 
four  distinct  classes,  as  follows :  (a)  animal  fibres,  (b)  vegetable 
fibres,  (c)  mineral  fibres,  (d)  artificial  fibres. 


6  THE   TEXTILE  FIBRES 

3.  Animal  and  Vegetable  Fibres. — According  to  their  origin, 
we  may  divide  the  principal  fibres  into  two  general  classes, 
those  derived  from  animal  and  those  derived  from  vegetable 
life.  The  former  includes  wool  and  silk,*  and  the  latter  cotton 
and  linen.  Animal  fibres  are  essentially  nitrogenous  sub- 
stances (protein  matter),  and  in  some  cases  contain  sulphur. 
Protein  matter  is  of  the  character  of  albumin,  and  forms  one  of 
the  principal  ingredients  of  animal  tissues.  It  is  essentially 
nitrogenous  in  composition  and  is  especially  characterized  by 
the  peculiar  empyreumatic  odor  evolved  when  burned. 
One  of  the  readiest  and  most  conclusive  tests,  in  fact,  which 
may  be  used  to  distinguish  between  an  animal  and  a  vegetable 
fibre  is  to  notice  the  odor  evolved  on  burning  in  the  air.  With 
regard  to  their  physical  condition,  it  may  be  said  the  proteids 
composing  the  animal  fibres  are  essentially  of  a  colloidal  nature; 
that  is,  they  resemble  a  solidified  jelly  in  condition.  This  property 
of  the  fibres  may  be  used,  to  a  great  extent,  to  explain  their  action 
with  solutions  of  dyestuffs  and  metallic  salts,  in  which  the  theory 
of  solid  solution,  adsorption,  and  osmosis  comes  into  play. 

Alkalies  readily  attack  the  animal  fibres,  causing  them  to  be 
dissolved,  but  they  withstand  the  action  of  mineral  acids  to 
a  considerable  degree.  Contrary  to  the  vegetable  fibres,  they 
are  readily  injured  if  exposed  to  elevated  temperatures. 

Vegetable  fibres  consist  of  plant-cells  usually  rather  simple  in 
structure  and  forming  an  integral  part  of  the  plant  itself. 
Plant-cells  are  of  different  character  and  size  depending  on  the 
part  of  the  plant  in  which  they  occur  and  the  office  or  function 
they  perform  in  the  development  of  the  plant  tissue.  These 
cells  consist  of  tubes  generally  between  o.ooi  in.  and  0.002  in. 
in  diameter;  their  ends  are  usually  pointed  and  in  their  arrange- 
ment overlap  one  another.  (See  Fig.  i.)  In  the  fibrous 
layers  occurring  in  plants  these  cells  are  sufficiently  long  and 
so  interlaced  as  to  give  a  fibre  of  considerable  strength,  whereas 
in  plain  woody  tissue  the  cells  are  short  and  properly  speaking 
yield  no  fibre  of  sufficient  strength  or  length  to  be  used  for 

*  Other  fibres  of  animal  origin  are  solid  filaments  formed  from  a  liquid 
secretion  of  certain  caterpillars,  spiders,  or  molluscs. 


CLASSIFICATION   OF  THE  TEXTILE   FIBRES 


textile  purposes.     In  monocotyledons,  according  to  Dr.  Morris, 

the  fibrous  cells  are  found  built  up  with  vessels 

into    a   composite    structure    known    as    fibro- 

vascular  bundles;    these  bundles  occur  in  the 

leaves  and  stems,  but  not  in    the   outer  bark 

of  plants  (see  Fig.  2),  and   are    usually  found 

imbedded  in    a    soft  cellular   tissue   known   as 

parenchyma.     The  vegetable  fibres  are  capable 

of  withstanding  rather  high  temperatures,  and 

are  not  weakened  or  disintegrated  by  the  action 

of  dilute  alkalies.      They  consist  essentially  of 

cellulose,  which  may  be  in  a  very  pure  form  or 

be  mixed  with  its  various  alteration  products. 

In  some  cases  the  fibre  consists  of  some  cellulose 

derivative  obtained  by  chemical  means,  such,  for 

instance,  as  mercerized   cotton.     Concentrated 

Cells  of  Wood 

alkalies    produce  alteration  products  with  the    Tissue     (xsoo) 

vegetable  fibres.     Free  sulphuric  or  hydrochloric 

acid,  even  if  only  moderately  strong,  will  quickly  attack  the 


Scl. 


Par. 


S.8. 


M.L. 


Scl  ^  PH.    B.S. 

FIG.  2. — Section  of  Fibrous  Plant  Cells  (Sisal  Hemp). 
Par,  cellular  parenchyma;    5.5.,  starch  layer;   Scl.,  sclerenchyma;  M.L.,  middle 
lamella;    B.S.,  bundle  sheath;    X,  xylem^or  wood  cells;    P.H.,  phloem  or 
bast  cells.     (After  Morris.) 


8  THE  TEXTILE   FIBRES 

fibre,  disintegrating  its  organic  structure  and  forming  hydrolyzed 
products.  Nitric  acid,  on  the  other  hand,  forms  nitrated  cel- 
luloses (the  so-called  nitrorcelluloses)  and  various  oxidation 
derivatives. 

It  is  generally  considered  that  the  animal  fibres  have  a 
lower  conductivity  for  heat  *  than  have  the  vegetable  fibres, 
and  in  consequence  fabrics  made  from  wool  and  silk  are  warmer 
than  those  made  from  cotton  and  linen,  f  From  actual  tests, 
however,  it  would  seem  that  this  quality  was  due  more  to  the 
structure  of  the  fabric  than  to  the  character  of  the  fibre. 

*  According  to  Dietz  (Wochenbl.  Papierfab.,  1912,  p.  3119)  the  specific  heats 
of  the  Various  fibres  are  as  follows: 

Raw  silk °-33i 

Boiled-off  silk °-33i 

Worsted  yarn ; 0.326 

Artificial  silk o .  3  24 

Linen 0.321 

Cotton 0.319 

Jute 0.324 

Kapok 0.324 

Hemp 0.323 

Manila  hemp 0.322 

Sisal  hemp o  .317 

Asbestos 0.251 

Glass  wool o.  157 

Straw 0.325 

Soda  wood  pulp 0.323 

Sulphite  wood  pulp 0.319 

T  Count  Rumford  made  some  interesting  experiments  relative  to  the  "  heat- 
retaining  value"  of  various  clothing  materials.  He  heated  a  large  thermometer 
to  a  given  temperature  and  then  ascertained  the  length  of  time  required  for  the 
thermometer  to  fall  to  a  given  point  when  surrounded  with  the  various  mate- 
rials experimented  upon.  The  times  taken  by  the  thermometer  in  falling  from 
70°  to  10°  Reaumur,  when  surrounded  with  various  substances,  were  as  follows: 

.  Seconds. 

Air '...' ..  .      ..  .      576 

Raw  silk :.........,.... :  .  . .  .  1 284 

Sheep's  wool 1 18 

Cotton 1046 

Fine  lint 1032 

Beaver's  fur 1 296  .  . 

Hare's  fur , 1315 

Eiderdown 1305 


CLASSIFICATION   OF  THE  TEXTILE  FIBRES  9 

4.  Mineral  Fibres;  Asbestos.— The  mineral  fibres  are  of 
rather  rare  occurrence  in  the  textile  industry  when  compared 
with  the  extensive  use  of  the  preceding  fibres.  They  find  a  lim- 
ited use,  however,  for  certain  purposes,  and  deserve  to  be  con- 
sidered in  a  systematic  study  of  the  subject.  The  principal, 
and  strictly  speaking,  the  only  mineral  fibre  is  asbestos,  which 
occurs  in  nature  as  a  mineral  of  that  name.  It  is  a  fibrous 
silicate  of  magnesium  and  calcium,  though  often  containing 
iron  and  aluminium  in  its  composition,  especially  in  the  dark- 
colored  varieties.  The  general  term  "  asbestos  "  includes  the 
fibrous  varieties  of  both  pyroxene  and  hornblende.  Pyroxene 
is  a  compound  silicate  of  magnesium  and  calcium,  always 
containing  iron,  and  generally  also  some  manganese.  Horn- 
blende (also  known  as  amphibole)  is  very  similar  in  composi- 
tion, but  often  contains  aluminium.  This  mineral,  though 
in  the  form  of  a  hard  rock,*  can  be  easily  separated  into  slender  f 
white  fibres  (Fig.  3),  sometimes  inclining  toward  a  greenish 
color.  The  fibres  of  some  varieties  are  curly,  and  afford  the 
best  material  for  spinning.  Asbestos  occurs  in  a  variety  of 
species,  some  of  which  are  much  more  valuable  than  others 
for  fibre  purposes.  In  some  the  fibres  are  slender  and  easily 

In  another  series  of  experiments,  however,  using  the  same  materials  differently 
arranged,  very  different  results  were  obtained: 

Seconds. 

Sheep's  wool,  loosely  arranged 1118 

Woolen  thread,  wound  round  bulb 934 

Cotton,  loose 1046 

Cotton  thread,  wound  round  bulb 852 

Lint,  loose 1032 

Linen  thread,  wound  round  bulb 873 

Linen  cloth,  ditto 786 

From  these  experiments,  Rumford  showed  that  the  heat-retaining  value  of 
clothing  depends  more  on  its  texture  than  on  its  actual  material.  For  further 
consideration  of  this  subject,  see  Mattieu  Williams'  book  on  The  Philosophy  of 
Clothing. 

*The  asbestos  mineral  has  a  density  of  2.5  to  2.8,  and  a  hardness  of 
3°  to  5°. 

f  The  individual  fibres  of  asbestos  are  so  fine  as  to  approach  the  limits  of 
microscopic  measurement  which  is  ^  =  0.0005  mm.  The  expression  y.  is  much 
used  in  microscopic  measurements;  it  is  the  accepted  symbol  for  the  micro- 
millimeter,  and  is  equivalent  to  the  one-thousandth  part  of  a  millimeter  =  0.00 1  mm. 


10 


THE  TEXTILE  FIBRES 


separable,  and  of  a  white  or  greenish  color.  A  variety  known 
as  Amianthus  gives  fibres  of  a  fine  silky  quality.  Ligniform 
asbestos  is  a  hard  compact  variety,  resembling  petrified  wood 
in  appearance,  and  brownish  to  yellowish  in  color;  a  wool- 
like  variety  found  near  Vesuvius  is  known  as  Breislakite.  Moun- 
tain flax,  mountain  cork,  and  mountain  leather,  are  all  varieties 
of  asbestos.  A  variety  of  serpentine  also  yields  an  asbestos, 
but  of  inferior  quality;  it  differs  from  the  hornblende  variety 
in  that  it  contains  about  14  per  cent  of  water  in  its  composition. 
The  mineralogical  name  for  this  fibrous  variety  of  serpentine 


FIG.  3. — Asbestos  Fibre.     (X5.)     (Micrograph  by  author.) 

is  chrysotile.  The  fibres  of  chrysotile  are  to  be  distinguished 
from  those  of  hornblende  by  the  fact  that  the  fibre-bundles 
of  the  former  are  partly  decomposed  by  hydrochloric  acid  and 
completely  so  by  sulphuric  acid,  whereas  hornblende  (or 
amphibole)  asbestos  is  not  acted  upon  by  either  acid.  Chrysotile 
asbestos  is  also  the  denser,  and  is  of  a  white,  straw-yellow  to 
brown,  or  blue  color,  depending  on  the  content  of  iron  oxide 
(which  is  sometimes  as  much  as  30  per  cent).  The  amphibole 
aslbestos  is  of  less  density  and  is  not  capable  of  being  spun; 
the  cplor  is  gray- white  to  pink.  It  occurs  in  commerce  cniefly 


CLASSIFICATION  OF  THE  TEXTILE   FIBRES  11 

in  the  powdered  form.  Chrysotile  can  only  withstand  a  temper- 
ature of  300°  to  500°  C.  without  loss  in  strength,  but  amphibole 
may  be  heated  to  1000°  to  1200°  C.  without  essential  alteration. 
Canadian  asbestos  is  the  most  valuable  as  a  source  for  textile 
purposes,  as  it  yields  a  curly  fibre  easily  spun  into  threads. 
In  general,  however,  the  fibres  of  asbestos  are  straight  and  glassy 
in  structure,  and  are  difficult  to  spin  into  a  coherent  thread. 
In  order  to  enhance  its  spinning  qualities  it  is  mixed  with  a 
little  cotton  or  linen,  the  latter  fibre  being  subsequently  destroyed 
by  heating  the  woven  fabric  to  incandescence.  By  improved 
methods  of  handling,  however,  it  is  now  possible  to  spin  asbestos 
directly  without  admixture  with  cotton;  the  asbestos  is  first 
softened  in  hot  water  and  then  disintegrated  mechanically 
into  the  fibre.  At  the  present  time  quite  a  variety  of  fabrics 
are  manufactured  from  asbestos  fibre,  and  the  high  quality 
of  many  articles  appearing  on  the  market  shows  that  the  art 
of  manipulating  this  substance  has  reached  a  high  degree  of 
perfection.  On  account  of  its  incombustible  nature,  and  as  it 
is  a  very  poor  conductor  of  heat,  it  is  made  into  fabrics  where 
these  qualities  are  especially  desired.  Thus  it  is  frequently 
manufactured  into  gloves  and  aprons,  packing  for  steam- 
cylinders,  theatrical  curtains  and  scenery,  lamp-wicks,  etc. 
The  latter  use  of  asbestos  was  known  to  the  ancients,  who 
employed  it  for  the  wicks  of  the  perpetual  lamps  in  their  temples. 
It  is  from  this  fact,  indeed,  that  it  received  its  name,  the  word 
"  asbestos  "  meaning  "  unconsumed."  It  was  also  employed 
for  napkins  on  account  of  being  readily  cleansed,  it  only 
being  necessary  to  heat  the  fabric  in  a  flame  to  make  it  clean 
again.  In  some  cases  asbestos  is  spun  directly  around  a  copper 
wire  for  purposes  of  insulation.  Asbestos,  in  general,  is  not 
dyed,  and  does  not  undergo  any  chemical  processes  or  modes 
of  treatment.  When  it  is  desirable  to  dye  it  the  various  sub- 
stantive dyes  may  be  used  with  good  effect,  or  the  color  may  be 
applied  by  mordanting  with  albumen. 

5.  The  Artificial  Fibres. — These  may  be  divided  into  two 
groups:  (a).  Those  of  mineral  origin  and  (b)  those  of  animal 
or  vegetable  origin.  In  the  first  division  may  be  classed  such 


12  THE  TEXTILE   FIBRES 

fibres  as  spun  glass,  metallic  threads,  and  slag  wool;  in  the 
second  division  may  be  put  the  various  artificial  silks,  such 
as  lustra-cellulose  and  gelatin  silk. 

Fibres  of  spun  glass  are  prepared  by  drawing  out  molten 
glass  in  the  form  of  very  fine  threads.  It  is  said  that  such 
threads  can  be  drawn  out  so  fine  that  it  takes  about  1400  miles 
of  the  fibre  to  weigh  one  pound.  Colored  glasses  may  be  used 
to  give  rise  to  variously  colored  threads.  Owing  to  its  brittle 
nature  and  lack  of  elasticity,  spun  glass  receives  a  very  limited 
application,  it  being  made  into  various  ornamental  objects, 
and  sometimes  into  cravats.  Though  fabrics  composed  entirely 
of  glass  are  rare,  yet  colored  glass  threads  are  somewhat  used 
for  the  weft  in  silk  materials  for  the  purpose  of  producing  novel 
effects,  as  the  glass  gives  the  fabric  great  lustre  and  stiffness.  A 
variety  of  spun  glass  known  as  glass  wool  is  used  to  some  extent 
in  the  chemical  laboratory  as  a  filtering  medium  for  liquids 
which  would  destroy  ordinary  filter-paper.  Glass  wool  is  curly, 
this  property  being  given  to  it  by  drawing  out  the  glass  thread 
from  two  pieces  of  glass  of  different  degrees  of  hardness;  and 
by  unequal  contraction  on  cooling,  this  double  thread  curls  up. 

Various  metals  are  at  times  drawn  out  into  threads  for  use 
in  decorative  fabrics.  Gold,  silver,  copper,  and  various  alloys 
are  used  for  this  purpose,  the  metals  being  heated  to  redness 
or  until  they  are  in  a  softened  condition.  At  the  present  time 
metallic  threads  are  largely  imitated  by  coating  linen  yarns 
with  a  thin  film  of  gold  or  silver;  Threads  of  pure  gold  are  sel- 
dom made;  what  is  known  as  "  pure-gold  "  thread  is  a  fine 
silver  wire  covered  with  a  thin  layer  of  gold.  Silver  thread  is 
sometimes  made  with  a  core  of  copper  and  a  layer  of  silver. 
Lyon's  gold  thread  consists  of  copper  faced  with  gold.  Metallic 
threads  are  usually  made  into  a  flattened  or  band-like  form  by 
rolling;  by  twisting  with  silk  or  woolen  yarns,  the  so-called 
"  brilliant  "  yarns  are  made.  The  Cyprian  gold  thread  of  old 
embroideries  consists  of  a  linen  or  silk  thread  around  which 
is  twisted  a  cover  of  gilded  catgut. 

Bayko  metal  yarn  is  a  textile  product  recently  introduced.* 

*  By  Bayer  &  Co.,  of  Elberfield. 


CLASSIFICATION  OF  THE  TEXTILE   FIBRES  13 

It  consists  of  a  core  of  cotton,  silk,  or  other  thread,  which  is 
coated  with  a  solution  of  cellulose  acetate  containing  in  suspen- 
sion finely  divided  particles  of  metals.  The  yarn  is  thus  given 
a  metallic  coating,  yet  furnishes  a  durable  and  flexible  thread. 
Microscopical  examination  of  this  yarn  shows  each  filament 
to  consist  of  a  core  or  nucleus,  and  an  enveloping  layer.  The 
core  is  usually  a  twofold  cotton  thread,  while  the  envelope  is  a 
colorless  to  pale  yellow  substance.  The  average  cross-section 
of  a  single  filament  is  0.0372  sq.mm.  The  cross-section  of  the 
envelope  is  0.0133  sq.mm.,  or  35.8  per  cent  of  the  total.  The 
metric  size  averaged  29.6;  the  thickness  of  the  filament  0.191 
mm.;  the  tensile  strength  averaged  462  gms.,  and  the  elasticity 
4.9  per  cent. 

Metallic  threads  are  used  for  quite  a  large  number  of  fabrics, 
such  as  passementerie  work,  trimmings,  brocades,  decorative 
embroidery,  church  vestments,  fancy  costumes,  tapestries, 
fancy  vestings,  etc. 

Slag  wool  is  prepared  by  blowing  steam-  through  molten 
slag;  it  can  scarcely  be  called  a  textile  fibre,  but  it  is  used  in 
some  degree  as  a  packing  material. 

Artificial  silks  are  made  either  from  cellulose  derivatives  or 
gelatin  by  forcing  solutions  of  these  through  fine  capillary 
tubes,  coagulating  the  resulting  threads,  and  subsequently 
subjecting  them  to  various  processes  of  chemical  treatment. 
As  these  belong  more  strictly  to  the  class  of  true  textile  fibres, 
they  will  be  given  a  more  extensive  consideration,  in  a  further 
section,  as  being  derivatives  of  cellulose. 


CHAPTER  II 

WOOL  AND  HAIR  FIBRES 

i.  The  Sheep. — The  wooly,  hair-like  covering  of  the  sheep 
forms  the  most  important  and  the  most  typical  of  the  textile 
fibres  which  are  obtained  from  the  skin  tissues  of  different 
animals.  The  hairy  coverings  of  a  large  number  of  animals 
are  employed  to  a  greater  or  lesser  extent  as  raw  materials  for 
the  manufacture  of  different  textile  products,  but  those  of  the 
various  species  of  sheep  make  up  the  great  bulk  of  the  fibres 
which  possess  any  considerable  technical  importance.  Hairs, 
derived  from  whatever  species  of  animals,  have  very  much  in 
common  as  to  their  general  physical  and  chemical  properties; 
they  are  also  similar  with  respect  to  their  physiological  origin 
and  growth.*  The  hairs,  however,  of  different  animals  vary 
much  in  the  detail  of  their  special  characteristics-,  and  also  with 
regard  to  their  adaptability  for  use  in  the  textile  industry; 
and  the  wool  of  the  sheep  appears  to  exhibit  in  the  highest 
degree  those  specific  properties  which  make  the  most  suitable 
textile  fibre.  These  properties  may  be  enumerated  as  being: 
(a).  Sufficient  length,  strength,  and  elasticity,  together  with 
certain  surface  cohesion,  to  enable  several  fibres  to  be  twisted 
or  spun  together  so  as  to  form  a  coherent  and  continuous 

*  An  animal  hair  consists  of  the  root  situated  in  a  depression  of  the  skin  (hair 
follicle)  and  the  shaft,  or  hair  proper.  In  the  typical  hair  three  sharply  defined 
tissues  are  present:  the  epidermis,  or  cuticular  layer,  the  cortex,  or  fibre  layer, 
and  the  medulla,  or  pith.  Hairs  are  distinguished  according  to  their  length, 
stiffness,  etc.,  as  bristles,  bristle  hairs,  beard  hairs,  and  woo'.  The  long  stiff  elastic 
hairs  of  the  hog  are  typical  bristles.  Bristle  hairs  are  s.iort,  straight  stiff  hairs 
with  a  medulla,  such  as  the  body  hairs  of  the  horse.  Beard  hairs  are  the  long, 
straight,  or  slightly  wavy,  regularly  distributed  hairs  (generally  with  a  medulla) 
which  give  the  pelts  of  various  animals  their  value.  Human  hair,  and  the  hair 
from  the  manes  and  tails  of  horses,  belong  to  this  class.  Wool  hairs  are  soft 
and  flexible.  (Hanausek,  Microscopy  of  Technical  Raw  Materials,  p.  123.) 

14 


WOOL  AND  HAIR  FIBRES  15 

thread  or  yarn;  (b)  the  power  of  absorbing  coloring  matters 
from  solution  and  becoming  dyed  thereby,  and  also  the  property 
of  becoming  decolorized  or  bleached  when  treated  with  suitable 
chemical  agents;  (c)  in  addition  to  these  qualities,  which  they 
have  in  common  with  almost  any  textile  fibre,  wool  fibres  also 
possess  the  quality  of  becoming'  felted  or  matted  together, 
due  to  the  peculiar  physical  character  of  their  surfaces.  This 
property  is  a  most  valuable  one,  as  it  adapts  wool  to  a  large 
number  of  uses  to  which  other  fibres  are  unsuitable. 

Silk  is  also  a  member  of  the  general  group  of  animal  fibres 
and  though  it  possesses  certain  general  chemical  characteristics 
in  common  with  wool  and  hair,  yet  it  has  an  entirely  different 
physiological  origin,  being  a  filament  of  animal  tissue  excreted 
by  a  certain  species  of  caterpillar,  and  hence  is  totally  different 
from  wool  in  its  physical  properties.  There  is  also  a  distinct 
chemical  difference  in  wool  and  silk.  The  former  contains  sul- 
phur as  an  essential  constituent,  while  the  latter  contains  no 
sulphur  in  its  composition.  Wool  may  be  specifically  designated 
as  a  variety  of  hair  growing  on  certain  species  of  mammalia, 
such  as  sheep,  goats,  etc.  The  unmodified  term  "  wool  "  has 
special  reference  to  the  product  obtained  from  the  different 
varieties  of  sheep.  Cashmere,  mohair,  and  alpaca  are  the 
products  obtained  from  the  thibet,  angora,  and  llama  goats, 
respectively.  Fur  is  also  a  modified  form  of  hair,  but  differs 
from  wool  in  many  of  its  physical  properties,*  and  is  not  adapted 
for  use  in  the  manufacture  of  spun  textiles.  It  is,  however, 
largely  employed  for  the  making  of  hat  felts.f 

The  wool-bearing  animals  all  belong  to  the  order  Rum- 
inantia,  which  includes  those  animals  that  chew  their  cud  or 
ruminate.  The  principal  members  of  this  order  are  sheep, 
goats,  and  camels.  The  sheep  belongs  to  the  class  Ovidw,  and 
occurs  in  a  number  of  species  which  vary  considerably  in  form 
and  geographical  distribution,  as  well  as  in  the  character  of  the 

*  The  cross-section  of  wool  is  almost  circular,  while  that  of  fur  is  quite  elliptical. 

t  The  fur  of  the  hare,  rabbit,  and  cat  is  occasionally  mixed  with  cotton,  wool, 
or  waste  silk  and  spun  into  yarns.  Such  yarns  are  principally  used  for  the  weav- 
ing of  certain  kinds  of  velvets. 


16  THE  TEXTILE   FIBRES 

wool  it  produces.     Broadly  considered,  naturalists  divide  the 
sheep  into  three  different  classes:  * 

(a)  Oms  aries,  commonly  known  as  the  domestic  sheep,  and 
cultivated  more  or  less  in  every  country  in  the  world. 

(b)  Oms  musmon,   occurring  native   in   the   European   and 
African  countries  bordering  on  the  Mediterranean  Sea. 

(c)  Oms    ammon,    which    includes    the     wild    or    mountain 
sheep  (argali)  to  be  found  in  Asia  and  America.     The  big-horn 
sheep  of  the  Rocky  Mountains  belongs  to  this  class. 

A  more  detailed  classification  than  the  above  is  given  by 
Archer,  who  divides  the  sheep  into  thirty- two  varieties: 

1.  Spanish,  or  merino  sheep  (Oms  his-       J7-  Javanese  sheep. 

panics).  1 8.  Barwall  sheep  (Ovis  barwal). 

2.  Common  sheep  (Ovis  rusticus).  19-  Short-tailed  sheep  of  northern  Rus- 

3.  Cretan  sheep  (Oms  strepsiceros).  sia  (Ovis  brevicaudatus) . 

4.  Crimean  sheep  (Ovis  hngicaudatiis).  20.  Smooth-haired    sheep    (Ovis   ethio- 

5.  Hooniah,  or  black-faced  sheep  of  pid). 

Thibet.  21.  African  sheep  (Ovis  grienensis}. 

6.  Cago,  or  tame  sheep  of  Cabul  (Ovis      22.  Guinea  sheep  (Ovis  ammon  guinecn- 

cagid).  sis). 

7.  Nepal  sheep  (Ovis  selingid).  23.  Zeylan  sheep. 

8.  Curumbar,  or  Mysore  sheep.  24.  Fezzan  sheep. 

9.  Garar,  or  Indian  sheep.  25.  Congo  sheep  (Ovis  dries  congensis). 
10.  Dukhun,  or  Deccan  sheep.  26.  Angola  sheep   (Ovis  aries  angolen- 
u.  Morvant  de  la  Chine,  or  Chinese  $/$). 

sheep.  27.  Yenu,  or   goitred   sheep  (Ovis  aries 

12.  Shaymbliar,  or  Mysore  sheep.  stcaliniora) . 

13.  Broad-tailed  sheep  (Ovis  laticauda-       28.  Madagascar  sheep. 

tus).  29.  Bearded  sheep  of  west  Africa. 

14.  Many-horned  sheep  (Ovis  polycera-      30.  Morocco  sheep  (Oils  aries  numidia). 

tus).  31.  West  Indian  sheep  of  Jamaica. 

15.  Pucha,  or  Hindoostan  dumba sheep.       32.  Brazilian  sheep. 

1 6.  Tartary  sheep. 

•  These  represent  the  naturally  occurring  classes  of  sheep  in 
the  different  countries;  of  course,  a  large  number  have  been 
emigrated  and  domesticated  in  other  countries  than  those  in 

*  Bowman  suggests  the  classification  of  sheep  into  the  following  three  divi- 
sions, based  on  the  length  of  the  average  fibres: 

(1)  Short,  fine,  pure-wooled  sheep,  such  as  the  merino  or  Southdown. 

(2)  Medium-staple  and  cross-bred  sheep,  such  as  those  from  which  the  fine 
combing  Australian  wools  are  obtained. 

(3)  Long-wooled,  bright-haired  sheep,  such  as  Leicester  and  Lincoln  breeds. 


WOOL  AND   HAIR  FIBRES  17 

which  they  had  their  origin,  which  has  given  rise  to  several 
sub-varieties.  Then,  too,  new  varieties  have  been  formed 
by  cross-breeding  and  intermixing,  which  has  brought  about  a 
considerable  variation  in  the  type.  The  latter  is  also  influenced 
very  largely  by  climatic  conditions,  geographical  environment, 
and  character  of  pasturage. 

The  domestic  sheep  is  the  most  important  of  these  classes.* 
It  can  hardly  be  said  to  be  indigenous  to  any  one  country,  for 
it  appears  to  have  been  cultivated  by  the  earliest  peoples  in 
history,  and  it  has  spread  over  the  entire  face  of  the  globe 
with  the  gradual  extension  of  civilization  itself,  f  Different 
conditions  of  climate  and  soil,  of  pasturage  and  cultivation, 
appear  to  exert  a  considerable  influence  on  the  variety  of  the 
sheep  and  on  the  character  of  the  wool  it  eventually  produces. 
Variations  are  also  produced  by  cross-breeding  and  intermixing, 
and  the  nature  of  the  fibre  has  been  much  altered  and  improved 
by  careful  selection  in  breeding  and  genealogical  development.  { 

2.  Classification  of  Fibres  in  Fleece. — Sheep  in  their  natural 
condition  produce  two  kinds  of  hair:  the  one  giving  a  long, 
stiff  fibre,  which  we  will  call  "  beard-hair  ";  and  the  other  a 
shorter,  softer,  and  more  curly  fibre,  which  we  will  designate 

*  This  sheep  yields  by  far  the  greater  portion  of  the  wool  of  commerce.  Other 
varieties,  such  as  the  Hungarian  sheep,  the  Zigaja  sheep,  the  Moorland  sheep, 
etc.,  yield  an  inferior  fleece  consisting  of  a  mixture  of  wool  and  beard-hairs. 

f  The  first  actual  mention  of  sheep  in  England  appears  in  a  document  of  the 
year  712,  where  the  price  of  the  animal  is  fixed  at  one  shilling  until  a  fortnight 
after  Easter. 

|  The  following  diagram  shows  the  general  pedigree  of  wool: 


Merino 

1 

Mountain 

r~                      n 

Saxony         Merion         Spanish  Merino            Englisl 
!                            Long  We 

1 
i           Scotch 
ol        Black 
Faced 
1 
Mixed  Breeds 

Carpet 
Wool 

Australian 
Merino 

1 

English 
Southdown 

1 
English 
Half-breed 

Buenos  Ayres 
Merino 

I 

1 

1 

Cross-bred 


18  THE  TEXTILE  FIBRES 

as  "  wool-hair,"  or  true  wool.  By  domestication  and  proper 
cultivation  the  sheep  can  be  made  to  produce  the  latter  kind 
of  hair  almost  exclusively,  with  but  little  or  none  of  the  hairy 
fibre.  Herein  the  sheep  differs  essentially  from  the  goat,  as 
the  latter  will  always  produce  both  kinds  of  fibre,  though  the 
fineness  and  quality  of  its  hair  may  be  much  improved  by  proper 
cultivation.  In  well-cultivated  sheep  the  wool-hairs  are 
usually  united  in  tufts  or  locks  containing  a  hundred  or  more 
fibres.  Often  several  locks  are  connected  into  one  large  one 
called  a  staple,  the  hairs  joining  the  locks  together  being  known 
as  binders.  The  number  of  hairs  growing  on  each  square  inch 
of  the  sheep's  skin  is  between  4500  and  5500.  In  addition 
to  the  above-mentioned  varieties  of  hair,  most  sheep  grow 
more  or  less  short,  stiff  hairs,  or  undergrowth;  these  have 
no  value  as  textile  fibres.  It  must  be  mentioned,  however, 
that  the  exact  character  of  the  wool  on  the  individual  sheep 
varies  considerably  with  its  position  in  the  fleece;  on  the  extrem- 
ities of  the  animal  the  wool  becomes  more  hairy  in  nature,  and 
near  the  feet  the  short  undergrowth  of  stiff  hair  is  alone  to  be 
found.  The  texture,  length,  and  softness  of  the  fibre  also 
differ  considerably  in  different  portions  of  the  fleece.  Hence 
it  becomes  necessary,  in  order  to  obtain  a  homogeneous  mixture 
of  fibres  with  properties  as  constant  as  possible,  to  sort  out  the 
fibres  of  the  fleece  into  different  portions,  which  are  put  together 
into  different  grades  of  wool  stock.  This  operation  is  termed 
wool-sorting  and  grading,  and  is  an  important  step  in  the  manu- 
facture of  wool.  Different  varieties  of  wool  may  require  dif- 
ferent systems  and  degrees  of  sorting,  but  in  general  the  fleece 
is  roughly  divided  into  nine  sections,  given  as  follows: 

(1)  The  shoulders  and  sides  of  the  fleece  give  the  finest  and 
most  even  staples  of  fibre.     This  wool  possesses  the  best  strength, 
length,  softness,  and  uniformity  combined. 

(2)  The  lower  part  of  the  back  yields  a  fibre  of  fairly  good 
staple,  and  somewhat  stronger. 

(3)  The  loin  and  back  give  a  shorter  staple,  and  the  fibre 
is  not  as  strong,  and  liable  to  be  sandy. 


WOOL  AND   HAIR   FIBRES  19 

(4)  The  upper  part  of  the  legs  give  a  staple  of  moderate 
length.     The  fibre  on  this  part  is  frequently  in  the  form  of  loose, 
open  locks  and  acquires  a  large  amount  of  burrs  by  brushing 
against  the  spinose  fruit  of  the  plant;    the  presence  of  these 
burrs  considerably  lessens  the  commercial  value  of  the  wool. 
South  American  wool  is  especially  liable  to  be  heavily  charged 
with  burrs. 

(5)  The  upper  part  of  the  neck  gives  a  rather  irregular 
staple  which  is  also  very  frequently  filled  with  burrs,  and  liable 
to  be  kempy. 

(6)  The   centre   of   the  back  gives    a   fine  delicate   staple 
similar  to  that  from  the  loins. 

(7)  The  belly,  together  with  the  wool  from  the  fore  and  hind 
legs,  yields  a  poor  staple  and  a  weak  fibre. 

(8)  The  tail  gives  a  short,  coarse,  and  lustrous  fibre,  fre- 
quently containing  a  considerable  amount  of  kemps. 

(o)  The  head,  chest,  and  shins  give  a  short,  stiff,  and 
straight  fibre,  opaque  and  dead  white  in  color. 

In  England  there  are  two  methods  of  sorting  generally 
employed.  The  first  is  known  as  the  Bradford  method,  in  which 
the  fleece  is  divided  into  two  portions  which  are  termed  the 
"  rigs  "  of  the  fleece.  The  second  is  the  Scotch  method,  in 
which  the  fleece  is  sorted  whole,  and  the  different  portions 
into  which  it  is  divided  are  termed  "  matchings ",  these  are 
known  by  different  terms:  (i)  super  is  the  finest  portion  of  a 
demi-lustre  fleece;  (2)  fine  is  the  best  part  of  the  shoulders  of  a 
fine  lustre  fleece  spinning  from  4o's  to  44's  counts;  (3)  blue 
is  from  the  shoulders  of  an  ordinary  lustre  fleece  (Lincoln  and 
Leicester);  (4)  neat  is  from  the  sides  of  an  ordinary  lustre 
fleece  spinning  from  32's  to  34's ;  (5)  brown  is  mostly  from  the 
flanks;  (6)  britch,  from  the  tail  and  thighs;  and  finally  (7) 
cow-tail,  the  lowest  matching  from  the  long-wooled  fleeces. 
In  fine  English  wools  there  are  two  further  matchings:  extra 
diamond  from  the  shoulders  of  an  English  "  down"  fleece,  and 
spinning  54's  to  56*3 ;  and  diamond,  which  is  from  the  sides 
of  the  same  fleece.  Brakes  is  a  term  used  to  designate  the 


20 


THE  TEXTILE  FIBRES 


TABLE    OF    THE    VARIETIES 


Varieties  and  Sub-varieties. 


Breed. 


CK 


Staple  of 
Fleece. 


i.  Spanish  (Ovis  hispania 
of  Linnaeus) 


2.  Common  Sheep  (Ovis 
rusticus  of  Linnaeus) .... 

Sub-variety  (a) ,  Hornless  or 
Lincolnshire .  .  . 


Sub-variety  (6),  Muggs  and 

Shetland 

Sub-variety  (c),  Ryeland  .  . 
Sub-variety  (d) ,  Southdown 


Sub- variety  (e),Old  Norfolk 

Sub-variety  (f),  Old  Wilt- 
shire   

Sub-variety  (g),  Cornish.  .. 

Sub-variety  (h),  Bampton. . 

Sub- variety  (i),  Exmoor, 
Notts 

Sub-variety  (j),  Cotswold.  . 

Sub- variety  (&),  Improved 

Teeswater 

Sub- variety  (/),  Silverdale  . 
Sub- variety  (m),  Penistone. 

Sub-variety  (n),  the  higher 

Welsh  Mountains 

Sub-variety  (o), Black-faced 


Spanish 

Class  i,  Estantes  or  Sta 
tionary 

(c)  Churrah 

(ft)   Merino 

Class  2,  Migratory. .  .  . 

Swedish 

French 

Danish 

Saxon 

Prussian 

Silesian .  . 


Hungarian 

Hanoverian 

New  South  Wales . 


Victorian 

W.  Australian .  . 
Queensland.  .  .  . 
New  Zealand.  .  . 
South  American. 
South  African.  . 
United  States.  . 
British.  . 


Lincolnshire. .  . 


Shetland . 
Hereford 
Sussex.  . 
Kent.  . 


Hampshire 


Norfolk .  . 
Wiltshire . 


Cornwall 

Devonshire 

Exmoor.  . 


Devonshire 

Durham,  York 

Lancashire 

West    Riding   of    York- 
shire 
The  Mountain  Sheep. .  . 


Westmorland 

Cumberland 

Northumberland 

Scotland 


Merino  and  native 

Merino  and  Roussillon. . 
Leonese  and  native .  .  .  . 
Merino  and  best  native 
Merino  and  native. .  . 


Merino  and  small  native 
Merino  and  Southdown 
Merino  and  Leicester. .  . 


Merino  and  Lincoln. .  .  . 
Merino  and  Southdown 

Lincoln  and  Leicester. .  . 


Southdown  and  Romney 

Marsh 
Southdown     and    old 

black-faced  Berkshire 
Southdown  and  Norfolk 

or  Downs 

Southdown  and  Wilt- 
shire 

Cornish  and  Leicester.  . 
Bampton  and  Leicester 
Exmoor  and  Leicester 

Cotswold  and  New  Lei- 
cester 

Teeswater  and  New  Lei- 
cester 

Penistone  and  Leicester 


Short 

Long  (8  in.) 
Short 

Long 

Medium 
Short 


Short 


Long 


Short 


Long 


Short 


Medium 


WOOL  AND  HAIR  FIBRES 
OF    FOREIGN    SHEEP 


21 


Quality. 

General  Color. 

Combing  or  Carding. 

General  Application. 

Spanish  wools  obtained  from 

— 

— 

— 

the  plains  are  of  the  merino 

Fine 

Black  andwhite 

Carding 

kind,  and  are  chiefly  used  for 

woolen  goods;    but  that  ob- 

Rather coarse 

White 

Combing 

tained  from  the  mountains  is 

Very  fine 

*  • 

Carding 

coarse  and  of  unequal  qual- 

— 

— 

— 

ity,  and  is  used  for  various 

Soft,  fine, 

White 

— 

low-class  goods 

Soft  and  very  fine 

'  ' 

— 

Dress  goods  and  cashmeres 

Fine 

1  ' 

Combing  and  carding 

Finest 

1  * 

1  ' 

Broad,  West  of  England,  bil- 

Very fine 

*  * 

*  4 

liard,  and  fine  dress  cloths. 

" 

4  • 

4  4 

Silesian  wool  is  almost,  if  not 

J       quite,  the  finest  in  the  world 

Fine 

4  * 

Carding 

— 

Very  fine 

" 

— 

— 

1  ' 

" 

Combing  or  carding 

Dress  goods,  coatings,  etc. 

'  • 

4  ' 

'  ' 

Meltons  and  pilots 

1  ' 

" 

Carding 

Hosiery 

Fine 

4  • 

Combing  or  carding 

*  * 

4  4 

4  4 

i,  Serges  for  suitings  and   dress 

•  ' 

4  • 

4  • 

goods 

44 

44 

" 

J 

" 

44 

,     44 

Coatings,  etc. 

" 

*  * 

4  * 

Dress  goods,  etc. 

" 

*  ( 

" 

Fine  dress  goods,    broadcloths. 

etc. 

Good  and  glossy 

44 

Combing 

These  are  amongst  the  finest  of 

the  long-stapled  lustre  wools; 

used  for  lustrous  worsteds  „ 

braids,  etc. 

Very  fine 

— 

" 

— 

Medium 

White 

44 

Fine 

White  and  gray 

Combing  and  carding 

Medium 

White 

4  4 

The  finest  British  wools;  used 

for  dress  fabrics,  serges  and 

flannels,  etc. 

Fine 

14  . 

«' 

J 

.. 

.. 

.. 

For  flannels  and  low  woolens 

Coarse 

.. 

,. 

Very  fine 

•• 

Combing 



Medium 

"    . 

Combing  and  carding 

— 

«• 

" 

Combing 

Worsted  and  serges 

Fine 

— 

•• 

— 

Good 

White 

.< 

Moderate 

'  * 

Carding 

— 

Fine 

" 

•• 

Blankets  and  flannels 

Coarse 

White  and  gray 

Combing  and  carding 

Blankets,  carpet  yarns,  etc. 

22 


THE  TEXTILE   FIBRES 


TABLE  OF  THE   VARIETIES  OF 


Varieties  and  Sub- varieties. 


Sub-variety  (/>),  Hebridean 
Sub- variety  (q),  Shetland.  . 
Sub-variety  (r),  Wicklow 

Mountains 

3.  Seling   (Ovi's  selingia    of 

Hodgson) 


4.  Curumbar 

Garar 

5.  Morvant  de  la  Chine.  .  . 


6.  Morocco  (Ovis  aries  nu- 
midioR  of  H.  Smith) 

7.  Yenu,  or  Goitred  Sheep. . 
Sub-variety,  Persian 


Sub- variety,  Fat-tailed.  .  .  . 

Sub-variety,  Russian 

Sub- variety,  Tibetan 

Sub-variety,  Cape 

Sub-variety,  Buenos  Ayres 


Breed. 


The  Hebrides. 

Shetland 

The  Irish .  . 


Nepaul,  central  hilly  re- 
gion, and  Eastern 
Tibet. 

Mysore 

India.  . 


China. 


Morocco , 


Angola . 
Persian 


Abyssinian 

Odessa 

Tibetan 

Cape  of  Good  Hope. . 
South  American  cross. 


Cross. 


Staple  of 
Fleece. 


Long 

Medium 

Long 
Short 


Long 

Short 
Fur-like 


skirting  or  edge  of  the  fleece;    it  is  always  used  for  woolen 
yarns.* 


*  The  following  table  (The  Text.  Mfr.,  1908,  p.  185)  shows  the  approximate 
amounts  of  the  different  qualities  contained  in  a  pack  (240  Ibs.)  of  fleeces: 


Quality. 

Lincoln  Hogs. 
Lb. 

Leicester  Hogs. 
Lb. 

Irish  Hogs. 
Lb. 

Fine  matchings  

17.57 

33  -9° 

34-  T3 

Blue  matchings  
Neat  matchings 

I49-03 
4C    77 

139.96 
44-  J8 

I44-30 
40.46 

First  brokes  

5.80 

5.19 

4.87 

Second  brokes  
Third  brokes  
Britch  

7-31 
2.67 

7-99 

5-03 
2.68 
6.00 

5-76 
3-54 
4-49 

Tail                   

i  .  31 

0.36 

0.60 

Cotts                      

o  31 

1.76 

i  .24 

Gray 

o  03 

O.O2 

ToDoings    . 

i  .45 

0,65 

0.50 

Waste          

1.16 

0.30 

0.12 

WOOL  AND  HAIR  FIBRES 
FOREIGN    SHEEP— Continued 


23 


Quality. 

General  Color. 

Combing  or  Carding. 

General  Application. 

Inferior 

White 

Combing  and  carding 

Tweeds,  etc. 

The  finest 

Carding 

— 

Medium 

— 

Carding  aod  combing 

Woolen  friezes,  etc. 

Fine 

Some  breeds 

Carding 

East  Indian  wools  are  used  for 

black 

• 

rugs,  carpets,  and  blankets 

f     White,      1 

Coarse 

yellow, 

|       gray, 

Carding 

Blankets,  low  tweeds,  etc. 

>  < 

brown, 

I       black       J 

Rather  coarse,  but 

Yellow 

it 

Rugs  and  carpets 

peculiarly      soft 

and  silky  to  the 

touch 

Inferior  fine  and 

White  and  gray 

•* 

Felts,  rugs  and  blankets 

soft 

Fine  and  close 

— 

— 

-.  — 

Medium 

White,  black. 

Combing 

— 

fawn,  yellow, 

brown,  gray 

Fine 

— 

— 

Worsteds 







Used  for  fur  trimmings 

Fine  but  burry 

— 

— 

Fine  woolens,  etc. 

The  merino  sheep,  which  yields  what  is  considered  to  be  the 
finest  quality  of  wool,  appears  to  have  originated  in  Spain,  and 
at  one  time  was  extensively  cultivated  by  the  Moors.*  The 
exportation  of  merino  sheep  from  Spain  was  long  guarded  against 
with  great  care,  no  one  being  allowed  to  take  a  live  merino 
sheep  out  of  the  kingdom  of  Spain  under  penalty  of  death. 
Later,  however,  this  sheep  was  brought  into  various  countries, 
being  crossed  with  the  different  local  breeds  with  very  beneficial 
results.  A  German  derivative  of  the  Spanish  merino  known 
as  the  Saxony  Electoral  merino,  gives  perhaps  the  highest 
grade  of  fibre  known  in  Europe.  Australian  sheep  are  mostly 

*  The  Spanish  merino  sheep  consisted  of  two  chief  races:  (i)  The  short-iegged 
Nigretti  sheep,  later  known  as  Infantados,  with  pronounced  neckfolds  and  a  dew- 
lap, and  (2)  the  tall,  long-legged  Escurial  sheep.  The  Saxon  Electoral  breed  is  a 
derivative  of  the  latter  race,  while  the  Austrian  Imperial  and  the  French  Ram- 
bouillet  breeds  are  derivatives  of  the  former.  The  English  breeds  of  long-wool 
or  lustre-wool  sheep,  including  the  Lincolns,  Leicesters,  and  Cotswolds  yield 
fleeces  consisting  chiefly  of  beard-hairs. 


24  THE  TEXTILE  FIBRES 

derived  from  merino  and  other  high-class  stock  and  yield  a 
wool  of  the  highest  quality.*  The  merino  has  been  culti- 
vated and  crossed  with  other  breeds  throughout  the  various 
parts  of  the  United  States,  and  the  latter  country  is  gradually 
becoming  a  large  producer  of  middle-grade  wool.f 

The  amount  of  fibre  in  the  fleece  varies  greatly  with  the 
breed,  sex,  age,  and  racial  conditions  of  the  animal.  The 
average  yield  from  the*  ewe  is  1.75  to  4  pounds,  and  from  the 
wether  3.5  to  7.5  pounds. 

The  first  shearing  from  a  two-year  old  sheep  is  known  as 
hog  (or  hogget)  wool,  while  that  shorn  from  a  sheep  which 
has  been  previously  clipped  is  known  as  wether  wool.  The 
finer  qualities  of  hog  wool  are  sometimes  known  as  teg  wool. 
In  hog  wool  the  natural  end,  or  point,  of  the  fibre  is  preserved 
whereas  in  wether  wool  both  ends  are  sheared. 

*  The  value  of  the  Australian  wool  clip  for  1905  was  estimated  at  over 
$92,500,000. 

t  According  to  the  National  Association  of  Wool  Manufacturers,  the  wool 
clip  for  1905  in  the  United  States  amounted  to  295,488,438  pounds;  during  the 
same  year  the  net  imports  of  wool  were  242,471,489  pounds,  giving  a  total  supply 
of  632,331,459  pounds.  The  imports  of  manufactures  of  wool  for  1905  amounted 
in  value  to  $21,373,742,  and  estimating  three  pounds  of  wool  in  the  grease  for  each 
dollar  in  value,  we  reckon  that  in  the  form  of  manufactured  goods  there  were 
imported  in  this  year  64,121,226  pounds,  which  added  to  the  takings  of  domestic 
mills  (478,667,887)  amounted  to  542,789,113  pounds  of  wool  as  approximately 
representing  the  consumption  of  wool  by  the  American  people  in  the  way  of 
domestic  and  foreign  manufactures,  which,  distributed  on  the  basis  of  the  popu- 
lation, amounted  to  6.54  pounds  of  wool  per  capita  required  to  meet  consumptive 
demand. 

The  total  imports  of  unmanufactured  and  manufactured  woolen  materials  for 
the  following  three  years  were  as  follows: 

Unmanufactured.  Manufactured. 

Lbs.  Value.  Value. 

1910 263,928,232  $51,220,844  $23,532,175 

1911 137,647,641  23,228,005  18,569,791 

1912 193,400,713  33,078,342  14,912,619 


WOOL  AND  HAIR  FIBRES 


25 


The  following  table  shows  the  chief  varieties  of  wool  (to  be 
met  with  in^England)  with  their  general  quality  and  use: 

PRINCIPAL  VARIETIES  OF  WOOLS — (English) 


Variety. 

Breed. 

Quality. 

Use. 

Staple. 

Spanish  
Silesian 
Saxony 
Australian.  .  .  . 

Merino  
Merino  and  cross 
bred 
Merino  

Cross-breds  
Queensland  

New  So  Wales 

Fine  
f   Fine                      \ 
i  Very  fine 
Very  fine  

Fine  

Very  fine 

Worsteds  and  woolens.  . 
Broad    cloths,     billiard 
cloths,  fine  dress  goods 
Fine   knitting   and   hos- 
iery yarns  
Do  
Fine  worsted  and  woolen 
cloths  
Meltons  and  pilots. 

Short 

11 

Victorian 

Hosiery. 

« 

« 

"     ; 

« 

New  Zealand.  . 

West  Australian  .  . 
Tasmanian.  ..... 
Cross-breds    with 
lustres  . 

Fine  
Fine  and  lustrous  . 

Serges  and  worsteds.  .  .  . 

Medium 

British  . 

Lincoln 

Good,  strong,  and 

Lustrous  worsteds. 

Leicester 

lustrous,  fine  to 

braids,  etc.      Raised 

,, 

Southdown 

coarse 
Finest  British  wool 

face  fabrics  and  hosiery 
Fine  worsted  and  woolen 

Long 
Short 

,  t 

Norfolk  downs. 

Fine 

cloths 
Do. 

« 

Suffolk  down 

Light  dress  goods 

« 

"       '.'.'.'.'.'.'. 

Dorset  
Romney  Marsh.  .  . 
Cotswold  

Cheviot  

Medium  
Medium  to  coarse 

Livery  cloth  and  woolens 
Woolens  and  carpets  .  .  . 
Worsteds,      cords     and 
serges 
Do..  . 

Medium 
Long 

Medium 

« 

Blackface  i 

Blankets   carpets   etc.- 

« 

Highland  wools  J 

Coarse  and  strong 

« 

« 

Welsh  

Medium,  fine  kem- 

Blankets  

•  « 

,, 

Irish  

py 

Medium  to  strong 

Heavy  woolen  and  friezes 

Long 

«. 

Herdwick 

Fine 

Short 

So.  American.  . 

Cent.  America 
So.  France.  .  .  . 
No    France 

Gloucester  
North  Hogs  
Buenos  Ayres.  .  .  . 
Merino  
Montevidean  
Vicuna  
Merino  
Cross-breeds  . 

Medium  
Medium  to  strong 
Very  fine;  burry.  . 

Fine  
Soft  and  fine  
Medium 

Worsted  and  woolens.  .  . 
Worsteds  

Fine  woolens  
Very  fine  cloths  
Dress  goods,  cashmeres 
Woolens 

Medium 
Long 
Short 

Long 
Short 

Algeria 

Native  sheep  . 

Inferior 

Felts   blankets  rugs 

Medium 

In-lia  

Horniah 

Coarse  and  kempy 
Coarse 

Blankets,  low  tweeds.  .  . 
Dress  goods   shawls  etc 

Long 

Odessa 

Fine 

Worsteds 

Short 

So.  Africa.  .  .  . 
Iceland  
Chinese 

Merino  
Astrakhan  
Merino                    -| 
Fat-tailed  An-       \ 
gora 

Morvant  de  la 

Very  fine  
Spec,  character.  .  . 

Various                   j 
I 
Fine   root,   coarse 
tip 
Fine  medium  

Broadcloth  and  serges  .  . 
Astrakhan  cloth  

Worsteds,    alpacas,   and 
woolens 

>  Woolens,  special 
Blankets,  rugs  and  car- 

Medium 
Short 

Cape  of  Good 
Hope 

Chine 

Fur  like 

pets 
Fur  trimmings  

Short 

Very  fine,  .  .  . 

Fine  cloths  

Long 

Shetland 

Fine 

Hosiery  

Short 

26 


THE  TEXTILE   FIBRES 


3.  Physiology  and  Structure  of  Wool. — Wool,  in  common 
with  all  kinds  of  hair,  is  a  growth  originating  in  the  skin  or 
cuticle  of  the  vertebrate  animals,  and  is  similar  in  its  origin  and 
general  composition  to  the  various  other  skin  tissues  to  be 
found  in  animals,  such  as  horn,  nails,  feathers,  etc.  Wool  is 
an  organized  structure  growing  from  a  root  situated  in  the 


FIG.  4. — Section  of  Hair  Follicle.     (Xioo.) 

C,  cuticle  of  skin;  R,  reta  mucosum;  PL,  papillary  layer;  5,  sebaceous  glands; 
P,  papilla;  B,  bulb  of  hair;  H,  hair;  F,  fibrous  tissue;  Sh,  transparent 
sheath.  (Micrograph  by  author.) 

dermis  or  middle  layer  of  the  skin,  its  ultimate  physical  elements 
being  several  series  of  animal  cells  of  different  forms  and  prop- 
erties. Herein  it  differs  essentially  from  silk,  which  is  not 
composed  of  cells,  but  is  a  continuous  and  homogeneous  tissue. 
The  root  of  the  wool  fibre  is  termed  the  hair  follicle  (Fig.  4); 


WOOL  AND  HAIR  FIBRES  27 

it  is  a  gland  which  secretes  a  lymph-like  liquid,  from  which  the 
hair  is  gradually  developed  by  the  process  of  growth.  The  hair 
follicle  also  secretes  an  oil,  which  is  supplied  to  the  fibre  during 
its  growth  and  serves  the  purpose  of  lubricating  its  several 
parts,  giving  it  pliability  and  elasticity.  In  conjunction  with 
the  hair  follicle  there  also  occur  in  the  skin  numerous  sebaceous 
glands  which  secrete  a  fatty  or  waxy  substance,  commonly 


FIG.  5. — Wood  Fibre  in  the  Grease.     (X5oo.) 

A,  irregular  lumps  of  grease  and  dirt;    also  note  that  outline  of  scales  is  very 
indistinct.     (Micrograph  by  author.) 

known  as  wool-fat.  This  substance  gradually  exudes  from  the 
glands  and  coats  the  surface  of  the  wool  in  rather  a  considerable 
amount  (Fig.  5).  It  affords  a  protective  coating  to  the  fibre 
which  serves  to  preserve  the  latter  from  mechanical  injury 
during  its  growth,  and  also  prevents  the  several  fibres  from 
becoming  matted  and  felted  together.  In  the  preparation  of 
wool  for  manufacture,  thisfatty  covering  has  to  be  removed, 
the  operation  constituting  the  ordinary  process  of  wool  scouring 


28 


THE  TEXTILE   FIBRES 


(Fig.  6).  There  is  also  a  wool-oil  which  is  contained  in  the 
cells  of  the  fibre  itself,  and  is  a  true  constituent  of  its  substance. 
This  oil  should  not  be  removed,  as  its  removal  causes  the  fibre 
to  lose  much  of  its  elasticity  and  resiliency.  The  oil  amounts 
to  probably  about  i  per  cent  of  the  total  weight  of  the  fibre, 
whereas  the  external  fatty  matters  amount  on  an  average 
to  about  30  per  cent. 


FIG.  6.—  Typical  Wool  Fibres  after  Removal  of  Grease. 
(Micrograph  by  author.) 


Morphologically  considered,  the  wool  fibre  consists  of  three 
distinct  portions:  (a)  A  cellular  marrow,  or  medulla,  which 
frequently  contains  more  or  less  pigment  matter  to  which  the 
wool  owes  its  color;  (b)  a  layer  of  cellular  fibrous  substance  or 
cortical  tissue  which  gives  the  fibre  its  chief  strength  and 
elasticity;  (c)  an  outer  layer,  or  epidermis,  of  horn  tissue, 
consisting  of  flattened  cells,  or  scales,  the  ends  of  which  generally 
overlap  each  other,  and  project  outward,  causing  the  edge  of 
the  fibre  to  present  a  serrated  appearance  (Fig.  7).  This 
scaly  covering  gives  the  fibre  its  quality  of  rigidity  and  resistance 


WOOL  AND   HAIR  FIBRES  29 

to  crushing  strain;  it  also  causes  the  fibres  to  felt  together  on 
rubbing  against  one  another  by  the  interlocking  of  the  pro- 
jecting edges  of  the  scales  (Fig.  8). 

Any  one  of  these  three  physical  constituents  may  at  times 
be  lacking  in  a  fibre.  When  the  epidermal  scales  are  absent, 
they  have  simply  been  rubbed  off  by  friction;  this  condition 


FIG.  7. — Sections  of  a  Hair  Fibre.     (Xsoo.) 

a,  cross-section;  b,  longitudinal  section;  A,  epidermal  layer  of  scales;  B,  cortical 
layer  of  fibrous  cells;  C,  medullary  layer  of  round  cells.  (Micrograph  by 
author.) 

is  frequently  to  be  found  at  the  ends  of  long  beard-hairs.  The 
cortical  layer  of  fibrous  tissue  is  frequently  but  slightly  devel- 
oped, especially  in  cases  where  the  medulla  is  large;*  in  some 
instances,  indeed  (as  in  the  hair  of  the  doe),  the  cortical  layer 
appears  to  be  totally  absent  in  the  broadest  parts  of  the  fibre. 
The  medulla  is  very  frequently  absent,  or,  at  least,  shows  no 


FIG.  8. — Diagram  showing  Felting  Action  of  Wool.     (Drawing  by  author,) 

difference  in  structure  from  the  cells  of  the  surrounding  cortical 
layer  (Figs.  9  and  10) ;  this  occurs  more  especially  in  the  wool- 
hairs,  but  is  also  to  be  found  in  beard-hairs.*  On  the  other 

*  The  Zigarra  wool  of  southern  Hungary  has  beard  hairs  which  show  no  evi- 
dence of  medullary  cells. 


30 


THE  TEXTILE  FIBRES 


FIG.  9.— Typical  Wool  Fibre.     (Xsoo.) 


M 


FIG.  io.— Wool  Fibres  Deficient  in  Medullary  Cells.     (Xsoo.) 
A,  a  fibre  without  evidence  of  medullary  cells;  B,  a  fibre  showing  isolated  medul- 
lary cells  at  M.     (Micrograph  by  author.) 


WOOL  AND   HAIR  FIBRES  31 

hand,  the  medulla  is  occasionally  more  largely  developed  than 
the  cortical  layer,  and  becomes  the  principal  part  of  the  fibre, 
as  in  the  beard-hairs  of  the  doe  (Fig.  n). 

4.  Microscopy  of  Wool. — The  microscopic  appearance  of 
wool  is  sufficiently  characteristic  to  distinguish  it  from  all  other 
fibres.  Under  even  moderately  low  power  of  magnification 
the  epidermal  scales  on  the  surface  of  the  fibre  can  be  readily 


FIG.  ii. — Beard-hair  of  Doe.     (X350.)     Showing  small  development  of  cortical 
layer  and  large  medulla.     (Micrograph  by  author.) 

discerned,  while  neither  silk  nor  the  vegetable  fibres  present 
this  appearance  (Fig.  12).  The  scales  are  more  or  less  trans- 
lucent in  appearance,  and  permit  of  the  under  cortical  layer 
being  seen  through  them.  The  exact  nature,  structure  and 
arrangement  of  the  scales  differ  considerably  with  different 
varieties  of  wool.  In  fine  merino  wools,  for  instance,  the  indi- 
vidual scales  are  in  the  form  of  cylindrical  cusps,  one  somewhat 
overlapping  the  other;  that  is  to  say,  a  single  scale  com- 
pletely surrounds  the  entire  fibre  (Fig.  13,  M).  In  some 


32 


THE  TEXTILE  FIBRES 


varieties  of  wool,  on  the  other  hand,  two  or  more  scales  occur  in 
the  circumference  of  the  fibre  (Fig.  13,  T).  In  some  cases  the 
edges  of  the  scales  are  smooth  and  straight,  and  this  appears 
to  be  especially  characteristic  of  fine  qualities  of  wool;  the 
coarser  species,  on  the  other  hand,  possess  scales  having  serrated 
wavy  edges.  Usually  such  scales  are  much  broader  than  they 


w 


FIG.  12. — Comparison  of  Wool,  Cotton,  and  Silk  Fibres.     (Xsoo.) 

W,  wool  fibre,  showing  marking  of  scales;    C,  cotton;   S,  silk,  showing  irregular 

shreds  of  silk-glue  at  Sh.     (Micrograph  by  author.) 

are  long  and  are  very  thin.  The  length  of  the  free  or  projecting 
edge  of  the  scale  is  also  a  very  variable  factor;  in  some  wools 
the  scale  is  free  from  the  body  of  the  fibre  for  about  one-third 
of  the  length  of  the  former,  and  in  consequence  the  scale  pro- 
trudes to  a  considerable  extent;  such  wool  would  be  eminently 
suitable  for  the  preparation  of  material  which  requires  to  be 
much  felted  (Fig.  13,  M).  In  other  wools  the  free  edge  of  the 
scale  amounts  to  almost  nothing,  and  the  separate  members 


WOOL  AND   HAIR  FIBRES  33 

fit  down  on  one  another  closely,  and  are  arranged  like  a  series 
of  plates.  Wools  of  this  class  are  more  hair-like  in  texture, 
being  stiffer  and  straighter,  and  not  capable  of  being  readily 
felted  (Fig.  14).  The  wool-hairs  (the  long,  stiff  fibres  which 
have  previously  been  mentioned  as  occurring  to  a  greater  or 
lesser  degree  in  nearly  all  wools,  and  also  known  as  beard-hairs) 
usually  possess  this  structure.  The  felting  quality  of  wool 


FIG.  13. — Comparison  of  Different  Varieties  of  Wool.     (X5oo.) 
M,  merino  wool  with  only  a  single  scale  in  circumference  of  fibre;  T,  territory 
wool   with   two  or  more   scales;    C,    coarse    wool  with    numerous   scales. 
(Micrograph  by  author.) 

is  much  increased  by  treatment  with  acid  or  alkaline  solutions, 
or  even  boiling  water ;  the  effect  being  to  open  up  the  scales  to  a 
greater  extent,  so  that  they  present  a  much  larger  free  margin 
and  consequently  interlock  more  readily  and  firmly.  Woolen 
yarns,  and  woven  materials  made  from  such  yarns,  felt  much 
more  easily  than  worsted  yarns,  due  to  the  fact  that  the  fibres 


34  THE  TEXTILE  FIBRES 

of  the  former  lie  in  every  direction  and  the  interlocking  of  the 
scales  takes  place  more  easily. 

In  some  varieties  of  wool  fibre  the  scales  have  no  free  edge 
at  all,  but  the  sides  fit  tightly  together  with  apparently  no 
overlapping;  in  such  fibres  the  surfaces  of  the  scales  are  also 


FIG.  14.  FIG.  15. 

FIG.  14.— Wool  Fibre  with  Plate-like  Scales.     (X340.)     (Hohnel.) 

A,  portion  of  fibre  with  isolated  medullary  cells  at  i,  and  smooth  scales  e  fitting 

together  like  plates;  B,  portion  of  fibre  showing  medullary  cylinder  at  m. 

FIG.  15.— Wool  Fibre  with  Concave  Scales.     (X340.)     (Hohnel.) 

m,  medullary  cylinder  consisting  of  several  rows  of  cells;  e,  concave  scales  arranged 

in  a  plate-like  manner. 

more  or  less  concave  (Fig.  15).  This  structure  only  occurs 
with  thick,  coarse  varieties  of  wool.  Frequently  at  the  ends 
of  the  wool  fibre,  where  the  natural  point  is  still  preserved 
(as  in  the  case  of  lamb's  wool  from  fleeces  which  have  not  been 


WOOL  AND  HAIR  FIBRES 


35 


previously  sheared),  the  scales  are  more  or  less  rubbed  off  and 
the  under  cortical  layer  becomes  exposed  (Fig.  16,  P);  this 
appearance  is  quite  characteristic  of  certain  wools.  In  diseased 
fibres  the  epidermal  scales  may  also  be  lacking  in  places,  causing 
such  fibres  to  be  very  weak  at  these  points  (Fig.  16,  D). 

In  most  varieties  of  wools  the  scales  of  the  epidermis  may 
be  readily  observed  even  under  rather  low  powers  of  magni- 


FIG.  16. — Wool  Fibres  showing  Absence  of  Epidermal  Scales.     (X5oo.) 

D,  at  middle  portion  of  fibre,  probably  due  to  disease;    P,  at  point  of  fibre  of 

lamb's  wool.     (Micrograph  by  author.) 

fication,  while  under  high  powers  the  individual  scales  may  be 
seen  overlapping  one  another  like  shingles  on  a  roof,  and  show- 
ing pointed  thickened  protuberances  at  the  edges.  When  the 
fibre  becomes  more  hair-like  in  nature,  such  as  mohair,  alpaca, 
camel-hair,  etc.,  it  is  more  difficult  to  observe  the  individual 
scales,  as  these  fuse  together  to  a  greater  or  lesser  degree,  until 
the  true  hair  fibre  is  reached,  which  exhibits  scarcely  any 
markings  of  scales  at  all  under  ordinary  conditions.  By  treat- 


36  THE  TEXTILE   FIBRES 

ment  with  ammoniacal  copper  oxide,  however,  the  interscalar 
matter  is  dissolved  away,  and  even  with  true  hair  the  scaly 
nature  of  the  surface  may  be  observed. 

5.  The  Epidermal  Scales. — The  epidermal  layer  of  scales 
imparts  to  the  wool  fibre  its  characteristic  quality  of  lustre. 
Since  the  lustre  of  any  surface  is  due  to  the  unbroken  reflection 
of  light  from  that  surface,  it  may  be  readily  understood  that  the 
smoother  the  surface  of  the  fibre,  the  more  lustrous  it  will 
appear.  When  the  epidermal  scales  are  irregular  and  uneven, 
and  have  projecting  points  and  roughened  edges,  the  surface 
of  the  fibre  will  naturally  not  be  very  smooth  and  uniform,  and 
consequently  will  reflect  light  in  only  a  broken  and  scattered 
manner.  Such  fibres  will  not  have  a  high  degree  of  lustre.  On 
the  other  hand,  when  the  scales  are  regular  and  uniform  in 
their  arrangement,  and  their  edges  are  more  or  less  segmented 
together  to  form  a  continuous  surface,  the  fibre  will  be  smooth 
and  lustrous.  As  a  rule,  the  coarser  and  straighter  fibres  are 
the  more  lustrous,  as  they  approximate  more  closely  to  the 
•structure  of  hair,  which  has  a  smooth  surface.  The  lustre  of 
the  fibre  being  dependent  on  the  polished  surface  of  the  scales 
is  influenced  largely  by  any  condition  which  may  affect  the 
latter.  Treatment  with  chemical  agents,  for  instance,  which 
will  corrode  the  horny  tissue  of  the  scales  will  seriously  affect 
the  lustre,  as  is  evident  by  allowing  alkaline  solutions  to  act 
on  lustrous  wool  fibres.  High  temperatures  (and  especially 
dry  heat)  corrodes  the  epidermal  scales  and  shrivels  them  up, 
causing  the  fibre  to  lose  its  lustre.  In  the  various  mechanical 
processes  through  which  the  wool  must  pass  in  the  course  of  its 
manufacture,  the  scales  of  the  fibre  suffer  more  or  less  injury, 
being  torn  apart,  roughened,  and  loosened  from  the  surface. 
In  order  to  minimize  the  extent  of  this  injury  the  wool  is  gen- 
erally oiled,  so  that  the  surface  of  the  fibres  may  be  properly 
lubricated. 

The  felting  quality  of  wool  is  also  dependent  on  the  nature 
of  the  epidermal  scales,  as  pointed  out  above.  The  more  the 
free  edge  of  the  scale  protrudes  from  the  surface  of  the  fibre, 
the  more  easily  will  the  wool  felt. 


WOOL  AND   HAIR   FIBRES  37 

Bowman  gives  the  approximate  comparative  number  of 
scales  per  inch  in  different  varieties  of  wool  as  follows: 

Wool.  Scales,  per  inch.     Diam.  of  Fibre  (ins.). 

East  Indian 1000  o .  00143 

Chinese 1 200  o .  00133 

Lincoln 1400  0.00091 

Leicester 1450  0.00077 

Southdown 1 500  o .  00080 

Merino 2000  o .  00055 

Saxony 2200  o . 00050 

According  to  the  measurements  of  Hanausek,*  the  size 
of  the  epidermal  scales  on  different  forms  of  hair  fibres  are  as 
follows : 

No.  of  Epidermal 

Fibre.  Scales  per  mm. 

Length  of  Fibre. 

Sheep's  wool,  ordinary 105 

' '      prime 97 

' '      merino 114 

"      Electoral 100 

' '      Saxony 121 

Angora  v/ool 53 

\Yhite  alpaca 90 

Brown  alpaca 150 

Vicuna  wool 100 

Camel's  wool 90 

Hanausek  claims  that  the  number  of  scales  on  a  given 
length  of  hair  appears  to  be  constant  within  narrow  limits  for 
each  kind  of  hair,  and  that  in  the  case  of  wool  of  certain  animals, 
particularly  the  merino  sheep  and  Angora  goat,  the  results 
of  counting  tests  are  of  considerable  value  in  identification. 
The  scales  on  Angora  wool  seem  to  be  the  most  uniformly 
distributed. 

With  respect  to  the  variation  in  fibres  derived  from  dif- 
ferent kinds  of  sheep,  Bowman  gives  the  following  classification: 

(i)  Those  sheep  the  fibres  of  whose  wool  most  nearly 
approach  to  a  true  hair,  the  epidermal  scales  being  most  horny 
and  attached  most  firmly  to  the  cortical  structure.  This  class 

*  Jahresb.  Wien.  Hand.  Akad.,  1888,  vol.  16,  pp.  107-110. 


38  THE  TEXTILE   FIBRES 

includes  all  the  lustrous  varieties  of  wool,  besides  alpaca  and 
mohair. 

(2)  Those  where  the  epidermal  scales,  though  more  numer- 
ous than  in  the  first  class,  are  less  horny  in  structure  and  less 
adherent   to   the   cortical   substance   of   the  fibre.     This   class 
includes  most  of   the  middle-wooled   sheep   and   half-breeds.* 

(3)  Those  where  the  characteristics  of  true  wool  are  most 
highly  developed,  such  as  suppleness  of  fibre  and  fineness  of 
texture,   the  epidermal  scales  being  attached   to   the   cortical 
substance    through    the    smallest   part   of    their   length.     This 
class  includes  all  the  finest  grades  of  sheep,  such  as  the  merino 
and   crosses  with  it. 

The  rigidity  and  pliability  of  the  wool  fibre  are  also  largely 
conditioned  by  the  nature  of  its  epidermal  scales.  If  these 
fit  over  one  another  loosely  with  considerable  length  of  free 
edge,  the  fibre  will  be  very  pliable  and  plastic,  soft,  and  yield- 
ing, also  easily  felted.  Whereas,  if  the  scales  fit  closely  against 
one  another  and  have  little  or  no  freedom  of  movement,  the 
fibres  will  be  stiff  and  resistant,  and  not  easily  twisted  together 
nor  felted. 

6.  The  Cortical  Cells. — The  cortical  layer,  or  true  fibrous 
portion  of  the  fibre,  forms  the  major  constituent  of  wool.  It 
consists  principally  of  more  or  less  elongated  cells,  and  often 
presents  a  distinctly  striated  appearance,  the  striations  being 
visible  through  the  translucent  layer  of  scales.  The  individual 
cells  measure  from  0.0014  inch  to  0.0025  inch  in  length,  and 
from  0.00050  inch  to  0.00066  inch  in  diameter,  hence  are  ellip- 
tical in  form.  The  cells  may  be  separated  from  one  another 
by  a  careful  treatment  with  caustic  alkali.  To  this  cortical  tissue 
the  fibre  chiefly  owes  its  tensile  strength  and  elasticity.  When 
the  fibre  is  fine  in  staple,  the  cortical  cells  exhibit  more  or  less 
unevenness  in  their  growth  and  arrangement,  with  the  result 
that  the  fibre  is  contracted  on  one  side  or  the  other,  giving 
rise  to  the  waviness  or  curled  appearance  of  such  wools.  It 

*  When  two  varieties  of  sheep  are  crossed  in  breeding  the  wool  from  the  result- 
ing offspring  is  known  as  "cross-bred."  Such  wool  has  a  tendency  to  produce 
uneven  staple  unless  proper  care  and  selection  are  exercised  in  the  crossing. 


• 
WOOL  AND   HAIR  FIBRES  39 

is  best,  perhaps,  to  speak  of  the  wool  being  "wavy"  rather 
than  "  curled,"  as  the  latter  implies  usually  a  spiral  develop- 
ment which  involves  a  twisting  of  the  fibre,  and  in  wool,  as  a 
rule,  this  does  not  occur.  Coarse  wools  seldom  exhibit  this 
wavy  structure,  or  only  to  a  slight  degree,  the  waves  being 
long  and  irregular;  some  fine  stapled  wools,  on  the  other  hand, 
possess  short  and  very  regular  waves.  This  property  of  the 
fibre  adds  much  to  its  spinning  qualities,  and  also  to  the  resiliency 
of  the  yarn  or  fabric  into  which  it  is  manufactured.  Wool- 
hairs  exhibit  much  less  development  of  waves  than  the  true 
wool  fibres,  and  the  more  closely  the  animal  fibres  approximate 
to  the  structure  of  ordinary  hair,  the  less  pronounced  are  the 
waves.  Sheep's  wool  is  more  wavy  than  that  derived  from 
allied  species,  such  as  the  various  goats,  camel,  etc.  Mohair,, 
for  instance,  exhibits  no  wavy  structure  at  all.  The  exact 
cause  which  determines  the  wavy  quality  of  wool  is  but  ill- 
defined;  there  appears,  however,  to  be  some  connection  between 
the  waviness,  the  diameter  of  the  fibre,  and  the  number 
of  scales  per  inch.  The  following  table,  given  by  Bowman, 
shows  the  relation  between  the  number  of  waves  and  the 
diameter  of  the  fibre.* 

w     .  Waves  Diameter  of 

per  Inch.  Fibre  (ins.). 

English  merino 24-30  o .  00064 

Southdown 13-18  o .  00078 

11-16  o.ooioo 

Irish 7-1 1  o .  ooi  20 

Lincoln 3-5  o .  00154 

Northumberland 2-4  0.00172 

The  waviness  of  the  wool  fibre  may  be  temporarily  removed 
by  wetting  with  hot  water  and  drying  while  in  the  stretched 
condition. 

*  The  fineness  of  the  wool  fibre  appears  to  bear  a  definite  relation  to  its  wavi- 
ness, and  attempts,  therefore,  have  been  made  in  Europe  to  grade  the  fibre 
according  to  the  number  of  waves  in  one  centimeter,  as  follows:  Superelecta, 
over  ii ;  electa,  9-10;  prime,  7-9;  second  quality,  6-7;  third  quality,  5-6; 
fourth  quality,  4-5.  The  different  kinds  of  waves,  known  as  normal  bent,  close 
bent,  high  bent,  flat  bent,  and  long  bent,  also  appear  to  be  due  to  differences  in 
the  fineness,  although  but  little  is  known  on  this  point  as  yet. 


40  THE  TEXTILE   FIBRES 

7.  The  Medullary  Cells. — The  medulla ,  or  marrow,  of 
the  wool  fibre  consists  of  round  or  slightly  flattened  cells, 
usually  somewhat  larger  in  section  than  those  comprising  the 
cortical  layer  (Fig.  7,  C).  The  size  of  the  medulla  varies 
considerably  in  different  varieties  and  grades  of  wool,  and  even 
shows  large  variations  in  fibres  from  the  same  fleece.  At  times 
it  may  occupy  as  much  as  one-quarter  to  one-third  of  the  entire 
diameter  of  the  fibre;  and  again,  it  may  be  reduced  to  almost 
a  line,  or  even  disappear  completely.  Wool-hairs  exhibit  the 
presence  of  a  distinct  medulla  more  frequently  than  the  true 
wool  fibres.  The  latter  mostly  show  scarcely  any  inner  struc- 
ture at  all,  though  at  times  there  may  be  noticed  isolated- 
medullary  markings,  but  usually  the  fibre  is  so  transparent 
that  it  presents  no  markings  at  all.  In  camel-hair,  however, 
the  medullary  portion  shows  up  very  distinctly,  in  some  fibres 
appearing  as  a  continuous  dark  band  occurring  about  three- 
fourths  of  the  width  of  the  fibre,  while  in  other  fibres  it  shows 
a  well-defined  granular  structure.  In  hairs  of  some  other 
animals  the  medullary  part  exhibits  a  structure  which  is  dis- 
tinctly characteristic  of  the  fibre;  in  the  hair  of  the  cat,  for 
instance,  the  medullary  cells  appear  in  a  reticulated  form, 
and  in  the  hair  of  the  rabbit  they  occur  as  a  series  of  laminae 
very  regularly  superposed  on  each  other.  The  medullary  cells 
frequently  contain  pigment  matter,*  either  continuously  or 
in  isolated  cells;  and  this  may  occur  even  in  fibres  usually 
classified  as  white  wool.  Sometimes  the  pigment  permeates 
not  only  the  medulla,  but  also  the  -cells  of  the  cortical  layer, 
in  which  case  the  fibre  as  a  whole  appears  colored.  To  this 
class  belong  the  variously  colored  wools,  ranging  from  a  light 
brown  to  almost  a  black.  The  hair  of  camels,  goats,  and  other 
animals  is  also  more  or  less  colored,  and  to  a  much  more  general 

*  According  to  Bowman  (Structure  of  the  Wool  Fibre,  p.  267)  the  pigment 
occurring  in  sheep's  wool  has  the  following  composition: 

Per  Cent. 

Carbon 554° 

Hydrogen 4.25 

Nitrogen 8 . 50 

Oxygen 31 .85 


WOOL  AND   HAIR   FIBRES  41 

extent  than  sheep's  wool.  The  medulla  may  consist  of  a  single 
series  of  cells,  or  of  several  series  arranged  side  by  side;  some- 
times these  cells  occur  in  a  discontinuous  and  rather  irregu- 
lar manner,  the  intervening  spaces  of  the  medulla  being  filled 
with  air.*  The  walls  of  the  medullary  cells  are  generally  very 
thin  and  indistinct,  and  the  contents  consist  of  finely  granular 
masses,  air,  and,  in  the  case  of  colored  hairs,  of  pigment  granules. 
Usually  the  medulla  consists  of  a  continuous  axial  cylinder  of 
cells,  though  at  times  the  continuity  may  be  interrupted, 
resulting  in  isolated  cells  or  groups  of  cells,  forming  the  so- 
called  "  medullary  islands."  The  function  of  the  medulla 
is  to  provide  the  living  fibre  with  an  inner  canal  for  the  flow 
of  juices  whereby  it  receives  nourishment  for  its  growth.  It 
also  adds  much  to  the  porosity  of  the  fibre,  forming  a  capillary 
tube  whereby  the  latter  may  absorb  solutions  of  various  kinds, 
such  as  dyestuffs,  different  salts,  etc.,  allowing  these  to  gradually 
permeate  through  the  cortical  layer  as  well.  The  epidermal 
layer  of  scales  is  rather  impervious  to  the  transpiration  of 
solutions,  and  only  permits  of  their  entrance  into  the  fibre 
at  the  joints  of  the  scales,  so  it  may  be  seen  that  the  medulla 
of  the  fibre  becomes  an  important  adjunct  in.  the  chemical 
treatment  of  wool  in  the  processes  of  mordanting,  dyeing, 
and  bleaching.  It  might  also  be  noted,  in  this  connection, 
that  the  epidermal  scales  become  but  slightly,  if  at  all,  dyed 
when  various  coloring  matters  are  applied  to  the  fibre,  but 
remain  colorless  and  translucent.  Hence  it  may  be  readily  under- 
stood that  if  two  samples  of  wool  are  dyed  simultaneously,  the 
one  consisting  of  fibres  having  small  and  open  scales,  while 
the  other  has  a  thick  and  highly  resistant  epidermis,  the  result- 
ing color  on  the  two  samples  will  have  a  different  quality  or 
tone,  due  to  the  influence  on  the  latter  of  the  uncolored  and 
translucent  scales.  In  wools  where  this  influence  is  very  marked 
it  is  almost  impossible  to  obtain  rich  and  full  shades  of  color, 
due  to  the  transparency  and  lustre  of  the  surface,  which  allows 
of  considerable  white  light  being  refracted  through  the  fibre 

*  This  is  especially  true  of  cow-hair. 


42  THE  TEXTILE  FIBRES 

along  with  the  reflected  color.  This  also  explains  the  well- 
known  fact  that  the  longitudinal  surface  of  the  fibre  in  many 
cases  presents  a  different  tone  of  color  than  the  cut  ends,  the 
latter  usually  being  richer  and  deeper  in  tone;  as  may  be  noticed 
in  cut-pile  fabrics,  such  as  occur  in  rugs,  plushes,  etc.  In  some 
cases  the  epidermal  layer,  instead  of  being  highly  translucent, 
is  opaque  and  white;  this  is  true  of  many  varieties  of  coarse 
wool-hairs,  and  such  fibres  as  cow-hair,  etc.  In  such  instances 
the  dyed  fibre  will  lack  liveliness  of  tone  and  appear  rather  dead 
and  flat.  The  further  discussion  of  this  interesting  subject 
must  be  dealt  with  in  more  detail  in  the  study  of  shade  matching. 
Attention  is  merely  called  to  it  at  this  point  in  order  to  emphasize 
more  clearly  the  fundamental  cause  of  these  differences  in  color 
phenomena  as  lying  in  the  structure  of  the  fibre  itself. 

Frequently,  through  disease  or  other  natural  causes,  the 
medulla  of  the  wool  fibre  is  imperfectly  developed,  or  the 
scales  of  the  epidermis  are  cemented  together,  in  consequence 
of  which  the  wool  will  not  absorb  solutions  readily,  and  hence 
will  not  be  dyed  (or  mordanted)  at  all,  or  only  slightly.  These 
fibres,  which  are  known  as  kemps,  will  occur  through  the 
mass  of  the  wool  as  undyed  streaks,  and  will  give  the  yarn  or 
fabric  a  speckled  appearance.*  Not  only  may  this  condition, 
however,  be  brought  about  by  natural  causes,  but  it  may  at 
times  be  the  result  of  improper  manipulation  during  manu- 
facturing processes.  There  is  a  certain  class  of  wool,  for  instance, 
known  in  trade  as  pulled  wool;f  this  is  obtained  from  the  pelts 
of  slaughtered  sheep,  and  is  usually  removed  from  the  skin 
by  the  action  of  lime,  the  fibres  being  pulled  out  by  the  roots. 
In  the  process,  the  medulla  becomes  stopped  up  with  solid 
insoluble  particles  of  lime,  which  is  also  true  of  the  end  pores 
of  the  cortical  layer  and  the  joints  of  the  scales.  As  a  conse- 


*  Kempy  wool  is  said  to  be  due  to  undue  exposure  of  the  sheep  and  to  bad 
feeding.  It  is  also  more  noticeable  in  wools  grown  in  mountainous  regions. 
Kempy  wool  should  not  be  used  in  fabrics  intended  to  be  dyed  a  solid  color.  For 
blankets,  Scotch  tweeds,  horse-rugs,  mantle  cloths,  and  the  like,  the  occurrence 
of  kempy  fibres  in  the  wool  is  not  an  especial  drawback. 

t  This  is  also  known  as  tanners'  wool  and  glovers'  wool. 


WOOL  AND  HAIR  FIBRES  43 

quence,  the  fibre  is  very  difficult  to  impregnate  with  solutions, 
and  will  remain  more  or  less  completely  undyed.  This  non- 
porous  character  is  also  enhanced,  perhaps,  by  the  fact  that  the 
fibre  does  not  possess  a  freshly  cut  end,  but  still  retains  the  root, 
which  is  more  or  less  rounded  off  and  closed  by  the  coagula- 
tion and  hardening  of  the  juices  in  the  hair  follicle. 

The  medulla,  as  a  rule,  is  more  developed  in  beard-hairs 
than  in  wool-hairs,  and  more  in  coarse  grades  of  wool  than  in 
in  the  finer  qualities.  There  also  appears  to  be  more  or  less 
relation  between  the  breed  of  the  wool  and  the  morphological 
characteristics  of  the  medullary  cells,  although  this  is  a  sub- 
ject which  as  yet  has  been  but  little  studied.  At  times  the 
medullary  cells  exhibit  but  little  difference  from  those  of  the 
cortical  layer,  and  these  two  portions  of  the  fiber  become  con- 
tinuous in  their  appearance;  that  is  to  say,  no  line  of  demarca- 
tion can  be  drawn  between  the  medulla  and  the  surrounding 
cortical  layer. 

8.  Physical  Properties. — In  tensile  strength  and  elasticity, 
the  wool  fibre  varies  within  large  limits,  depending  on  the  breed 
and  quality  of  the  sheep,  and  also  the  diameter  of  the  fibre 
and  the  part  of  the  fleece  from  which  it  was  derived.  The 
strength  of  wool,  and  of  animal  hairs  in  general,  is  due  to  the 
peculiar  structure  of  the  fibre.  In  the  first  place,  the  external 
sheath  of  horny  tissue  of  flattened  cells  which  take  the  form 
of  scales,  offers  considerable  resistance  to  crushing  strains, 
and  are  also  locked  rather  firmly  together  in  the  direction  of 
the  length  of  the  fibre;  this  has  a  tendency  to  resist  any  diminu- 
tion in  the  diameter  of  the  fibre  which  would  be  felt  when  the 
latter  is  stretched.  Then,  too,  the  internal  cortical  cells  of  the 
fibre  are  so  arranged  as  to  present  a  very  firm  structure,  being 
firmly  interlaced  together,  consequently  they  offer  considerable 
resistance  to  rupture.  It  has  been  noticed  by  a  microscopical 
examination  of  a  broken  fibre  that  the  cells  themselves  are 
never  ruptured,  but  only  pulled  apart  from  one  another;  this 
is  evidence  that  the  cell- wall  is  of  a  strong  texture.  The  latter 
is  probably  formed  of  a  continuous  tissue  which  is  less  than 
0.0002  inch  in  thickness,  as  under  the  highest  powers  of 


44 


THE  TEXTILE  FIBRES 


the  microscope  it  exhibits  no  evidence  of  structural  elements. 
Bowman  gives  the  following  table,  which  records  the  average 
results  of  a  number  of  experiments  on  the  strength  and  elas- 
ticity of  the  wool  fibre: 


Wool. 

Tensile 

Strength, 
Grams. 

Elasticity, 
Per  Cent. 

Diameter, 
Inches. 

Human  hair  
Lincoln  wool 

1  06 

2? 

36.6 
28  4 

0.00332 
o  00181 

Leicester  

31 

27  .3 

o  00164 

Northumberland          

28 

27  o 

o  00149 

Southdown  wool  .  ,  

5.9 

26.8 

o  .  00099 

Australian  merino  

3  •  2 

33  •  ^ 

o  00052 

Saxony  merino  
Mohair... 

2-5 
?8 

2/0 

2Q    9 

o  .  0003  4. 
o  ooi  70 

Alpaca  

9  •  7 

24  .  2 

o  000^3 

It  is  interesting  to  compare  these  figures  of  tensile  strength 
for  equal  cross-sections  of  fibre.  As  the  cross-section  varies 
with  the  square  of  the  diameter,  by  taking  the  ratio  of  the 
latter  numbers  and  multiplying  by  the  tensile  strength,  a  figure 
is  obtained  which  represents  the  tensile  strength  for  equal 
diameters  of  fibres.  In  this  manner  the  following  table  has 
been  calculated,  taking  human  hair  as  the  standard  for  com- 
parison, as  it  has  the  largest  diameter: 

Human  hair . 100 

Lincoln  wool 06.4 

Leicester 1 19 . 9 

Northumberland 130 . 9 

Southdown  wool .  62.3 

Australian  merino 122.8 

Saxony  merino 224 . 6 

Mohair 136 . 2 

Alpaca 358  5 

Cotton  (Egyptian) 201 . 8 


It  will  be  noticed  from  this  table  that  Saxony  merino  wool 
is  by  far  the  strongest  of  the  different  grades  of  wool.     It  is 


WOOL  AND   HAIR   FIBRES 


45 


also  interesting   to  note   that   cotton  is   considerably  stronger 
than  the  majority  of  wools. 

Barker  *  has  given  the  comparative  strength  of  equivalent 
yarns  of  worsted  and  other  fibres,  as  follows: 


Yarn. 

Breaking  Strain,  Ounces. 

i  Inch  Test. 

27  Inches  Test. 

Tram  silk  (4)                  

45 
34-5 
29-5 
17 
II 

0 

7-5 

40 

24-5 
18 

13-5 
II 

5 
3-5 

Ramie  (12)                                       

Linen  (is)             •  •  •  

American  cotton  ^14)          

Viscose  silk  (2) 

Lustre  worsted  (Q) 

Botany  worsted  (9)  

The  size  of  the  yarn  in  each  case  is  equivalent  to  1/30' s 
worsted.  The  numbers  after  the  name  of  each  yarn  represent 
the  turns  per  inch,  being  the  respective  normal  amount  of 
twist  in  each  case.  The  figures  in  the  first  column  represent 
more  nearly,  probably,  the  actual  breaking  strain;  and  those 
in  the  second  column  represent  rather  the  slipping  strain  of 
the  yarn,  and  approximate  more  closely  to  the  true  weaving 
strength. 

In  length,  the  wool  fibre  varies  between  large  limits,  not 
only  in  different  sheep,  but  also  in  the  same  fleece.  Generally 
speaking,  the  length  may  be  taken  as  being  between  i  and  8 
inches.  The  diameter  of  the  fibre  is  also  very  variable,  even 
in  the  same  fleece,  but  may  be  taken  as  averaging  from  0.0018 
to  0.004  inch.f  According  to  their  length  of  staple,  wool 
fibres  are  graded  into  two  classes:  tops  and  noils.  The  former 
includes  the  longer  stapled  fibres,  which  are  combed  and  spun 
into  worsted  yarns,  to  be  manufactured  into  trouserings,  dress- 
goods,  and  such  fabrics  as  are  not  fulled  to  any  extent  in  the 

*  Jour.  Soc.  Dyers'  6*  CoL,  1905,  p.  36. 

f  According  to  Hohnel,  the  diameter  of  sheep's  wool  varies  from  10  to  100  [t. 
(the  expression  [A  =  nr?nT  mm.);  and  according  to  Cramer,  the  thickness  of  the 
hairs  from  one  and  the  same  fleece  may  vary  from  1 2  to  85  \JL. 


46  THE  TEXTILE  FIBRES 

finishing.  The  latter  class  consists  of  the  short-stapled  fibres, 
which  are  carded  and  spun  into  woolen  yarns  to  be  used  for 
weft  and  all  classes  of  goods  which  are  fulled  more  or  less  in  the 
finishing  operations,  where  a  felting  together  of  the  fibres  is 
desired.  On  comparing  worsted  and  woolen  yarns,  it  will 
be  noticed  that  the  former  are  fairly  even  in  diameter  and  the 
individual  fibres  lie  more  or  less  parallel  to  each  other,  whereas 
in  woolen  yarns  the  diameter  is  very  uneven,  and  the  fibres 
lie  in  all  manner  of  directions. 

9.  Conditions  Affecting  Quality  of  Wool. — The  quality 
of  wool  obtained  from  sheep  depends  very  largely  on  the  breed, 
climatic  conditions,*  and  nature  of  the  pasturage  on  which 
the  sheep  feed.  Australia  appears  to  possess  the  climatic 
conditions  best  adapted  for  wool-growing.t  With  regard 
to  the  nature  of  the  pasturage  it  has  been  found  that  grass  from 
chalky  soils  gives  rise  to  a  coarse  wool,  whereas  that  from  rich, 
loamy  soils  produces  fine  grades  of  wool.J  As  a  rule,  the  sheep 

*  Other  conditions  being  equal,  long  droughty  seasons  in  wool-growing  dis- 
tricts will  cause  the  fibre  to  be  much  shorter  than  otherwise. 

f  The  wool  fibre  appears  to  grow  to  best  advantage  in  a  temperate  climate, 
and  when  the  sheep  are  provided  with  dry  foods  and  pasture  upon  light  soils. 
Rain-falls  have  a  great  influence  on  the  wool  fibre;  fine  merino  wools  being  grown 
best  where  the  rain-fall  is  slight,  while  the  fibre  tends  to  become  coarse  where 
the  rain-fall  is  heavy.  Australia  has  a  temperate  climate,  a  light  soil,  and  the 
average  rain-fall  is  only  2  to  3  inches. 

J  Utah  wools,  for  instance,  are  harsh  and  stairy  compared  to  Wyoming  wools. 
This  is  due  to  the  alkali  in  the  soil  in  Utah  and  the  dryness  of  the  climate.  The 
alkali  in  the  soil  and  the  effect  it  has  upon  the  water  which  the  sheep  drink  have 
a  tendency  to  take  the  life  out  of  the  wool  and  weaken  the  staple.  The  more  close 
and  uniform  the  fibres  lie,  the  better  will  be  the  combing  qualities  of  the  wool. 
The  Utah  wools  in  this  respect  are  inferior  to  the  Wyomings,  Idahos,  and  Mon- 
tanas,  especially  the  wools  grown  in  southern  Utah.  In  northern  Utah  the  wools 
are  longer  than  in  southern  Utah,  but  there  are  very  few  Utahs  either  north  or 
south  which  are  fit  for  combing.  The  heaviest  shrinkage  wools  generally  come 
from  eastern  Oregon  and  Nevada.  The  degree  of  shrinkage  depends  to  a  con- 
siderable extent  on  the  season  in  which  the  wools  were  grown.  A  wet  season 
and  long-continued  rains  will  wash  much  dirt  and  dust  out  of  the  wools,  thus 
leaving  them  lighter.  The  lightest  shrinkage  wools  come  from  Virginia  and  Ken- 
tucky and  the  Blue  Grass  region,  where  medium  wools  are  grown,  where  the 
sheep  are  cleaner,  the  range  better,  and  the  country  hilly,  and  where  comparatively 
little  sand  and  dirt  work  their  way  into  the  fleece.  The  shrinkage  of  washed 
fleeces  ranges  from  55  to  35  per  cent.  Unwashed  Indiana  wools  shrink  38  to  43 


WOOL  AND  HAIR  FIBRES  47 

which  yield  the  best  qualities  of  wool  give  the  poorest  quality 
of  mutton. 

Unhealthy  conditions  of  the  sheep  almost  always  influence 
the  fibre  during  that  period  of  its  growth.  If  the  sheep,  for 
example,  is  suffering  from  indigestion,  cold,  lack  of  proper 
nourishment,  etc.,  the  fleece  during  that  time  will  develop  ten- 
der fibres ;  when  the  sheep  regains  its  normal  condition  of  health 
the  fibre  becomes  strong  again.  Thus  the  fleece  may  have 
tender  strata  through  it  which  will  considerably  affect  the  fibre 
and  its  uses.  These  tender  spots,  of  course,  render  the  wool 
unfit  for  combing  purposes,  and  it  must  go  into  the  "  clothing  " 
class,  and  will  consequently  sell  for  less  money,  other  things 
being  equal.  It  is  no  great  injury  to  the  wool,  however,  aside 
from  spoiling  it  for  combing,  as  the  wool,  after  it  has  passed  the 
tender  spot,  grows  fully  as  well  as  before  the  sheep  was  ill. 
When  sheep  have  been  afflicted  with  scab,  the  latter  shows 
itself  in  tender  wool  at  the  bottom  of  the  fibre.  The  scab 
leaves  a  pus-like  substance  which  adheres  to  the  bottom  of  the 
fibres  and  dries  there.  Vermin  on  sheep  have  an  influence  on 
the  wool ;  these  creatures  leave  discolorations  on  the  fibre  which 
cannot  be  removed  by  scouring.  The  wool,  being  "  off  color," 

per  cent.  Missouris  will  shrink  around  43  to  45  per  cent;  Illinois,  45  to  47  per 
cent.  California  wools  shrink  55  to  72  per  cent,  depending  on  the  part  from 
which  they  come.  The  heaviest  shrinkage  wools  are  in  southern  California, 
because  of  the  presence  of  more  sand  and  dirt,  and  inferiority  of  the  range.  Texas 
spring  wools  shrink  anywhere  from  64  to  72  per  cent,  and  the  fall  wools  58  to  64 
per  cent.  Territory  wools  shrink  from  55  up  to  73  per  cent.  Idahos  on  the  medium 
order  will  not  shrink  over  55  per  cent.  Wyoming  wools  on  the  fine  and  fine 
medium  order  shrink  65  tp  72  per  cent.  The  Mon tanas  shrink  on  the  average 
63  to  69  per  cent  for  fine  and  fine  mediums,  and  57  to  60  per  cent  for  mediums. 
The  shrinkage  on  Arizona  wools  will  range  from  66  to  73  per  cent,  but  they  will 
spin  to  finer  counts  than  the  Utah  wools,  and  will  scour  out  very  white.  In 
this  latter  respect  the  Wyoming  wools  are  superior  to  any  other  grown  west  of 
the  Mississippi  River.  The  shortest  wools  grown  in  America  are  from  California 
and  Texas;  they  are  used  principally  for  felts  and  hats,  though  they  can  also  be 
mixed_in  certain  proportions  with  clothing  wool.  As  the  Territory  wools  are 
grown  mostly  in  dry  climates,  they  will  gain  somewhat  in  weight  on  being  shipped 
to  the  Atlantic  seaboard  and  stored  for  a  few  months.  Utah  wools  will  gain  about 
i  per  cent,  Montana  wools  about  *  per  cent,  and  Wyoming  wools  about  i  per  cent. 
The  wools  from  Ohio  and  other  eastern  States  will  not  gain  anything;  in  fact, 
will  sometimes  show  a  slight  shrinkage.  (American  Wool  and  Cotton  Reporter.) 


48  THE  TEXTILE  FIBRES 

does  not  sell  as  well,  and,  moreover,  the  fibre  is  liable  to  be 
tender. 

As  to  the  amount  of  wool  to  be  obtained  from  each  sheep, 
it  may  be  said  that  the  average  yield  is  from  4  to  15  pounds, 
though  in  some  South  American  varieties  the  fleece  may  weigh 
as  high  as  30  to  40  pounds. 


CHAPTER  III 


THE    CHEMICAL  NATURE  AND  PROPERTIES  OF  WOOL  AND 
HAIR   FIBRES 

i.  Composition  of  Raw  Wool. — In  its  chemical  constitu- 
tion wool  is  closely  allied  to  hair,  horn,  feathers,  and  other 
epidermal  tissues.  A  distinction  must  be  made  between  the 
fibre  proper  and  the  raw  wool  as  it  comes  from  the  fleece.  In 
the  latter  condition  it  contains  a  large  amount  of  dirt,  grease, 
and  dried-up  sweat  which  have  first  to  be  removed  by  the 
scouring  process  before  the  pure  fibre  is  obtained. 

The  following  analysis  by  Chevreul  of  a  merino  wool  shows 
the  average  amount  of  fibre  to  be  obtained  from  raw  fleece  wool : 

Per  Cent. 
Earthy  matter  deposited  by  washing  the  wool  in  Water.      26.06 

Suint  or  yolk  soluble  in  cold  distilled  water 32.74 

Neutral  fats  soluble  in  ether 8.57 

Earthy  matters  adhering  to  the  fat i  .40 

Wool  fibre 31-23 


100.00 


These  figures  are  based  on  wool  dried  at  100°  C.;  if  cor- 
rected for  air-dry  wool  containing  14  per  cent  of  moisture, 
this  would  give  only  about  27.5  per  cent  of  pure  fibre.  Of 
course,  the  amount  of  fibre  will  vary  considerably  in  different 
qualities  and  samples  of  wools,  but  this  figure  may  be  taken 
as  a  fair  average. 

Wright  *  gives  the  following  analyses  of  greasy  wools: 


Constituents. 

Half 
Blood. 

Three-quarter 
Blood. 

Leicester. 

Lincoln. 

Moisture             

16.00 

10    3O 

1  7   07 

17    18 

Wool-fat 

16  68 

12    08 

8   Qd 

572 

Other  fatty  matter  

0.42 

O   74 

O   OI 

o  06 

Water  soluble  suint   

10.  30 

12    72 

7   8l 

2    26 

Sand  dirt  etc            

*  62 

302 

r    IO 

5-7  2 

Pure  wool  fibre 

<?2    08 

C  I      •72 

CQ      A£ 

68  56 

*  Jour.  Soc.  Chem.  Ind.,  1909,  p.  1020. 


49 


50  THE  TEXTILE  FIBRES 

2.  Wool  Grease;  Cholesterol. — The  fatty  and  mineral 
matters  present  on  the  raw  wool  fibre  consist  on  the  one  hand 
of  wool  grease  derived  from  the  fatty  glands  surrounding  the 
hair  follicle  in  the  skin,  and  on  the  other  hand  of  dried-up 
perspiration  from  the  sudorific  glands  in  the  skin.  The  wool 
grease  is  mostly  to  be  found  as  the  external  coating  on  the 
fibre  *  which  serves  to  protect  it  from  mechanical  injury  and 
felting  while  in  the  growing  fleece. 

Lack  of  natural  grease  on  the  fibres  of  the  growing  fleece 
results  in  the  production  of  so-called  cotted  fleeces.  In  such 
fleeces  the  fibres  have  grown  in  and  among  each  other  on  the 
sheep's  body,  so  that  they  form  a  more  or  less  perfect  mat  of 
wool.  These  mats  are  hard  or  soft  according  to  the  extent 
to  which  the  matting  process  has  been  carried  on.  Cotted 
fleeces  occur  mostly  in  sheep  which  have  been  housed;  they  are 
seldom  found  in  the  territories  where  the  sheep,  run  on  the 
range  and  are  more  exposed  and  hardy.  Cotted  fleeces  indi- 
cate a  low  degree  of  vitality,  and  many  are  to  be  found  in 
fleece  wool  from  States  east  of  the  Mississippi  River.  They 
may  be  caused  by  sickness  or  a  low  state  of  the  blood,  or  they 
may  be  found  in  an  old  sheep  which  is  giving  out  or  is  run 
down,  which  contributes  to  the  frowsy  condition  of  the  wool. 
Cotted  fleeces  are  unfit  for  combing  purposes,  as  they  have  to 
be  torn  apart,  and  frequently  they  are  so  dense  and  hard  that  the 
fibres  can  only  be  pulled  apart  by  the  use  of  special  machinery. 
Badly  cotted  fleeces  are  frequently  used  for  braid  purposes. 

There  is  also  a  small  amount  of  oily  matter  contained  in 
the  medullary  intercellular  structure  of  the  fibre  which  appears 
to  have  the  function  of  acting  as  a  lubricant  for  the  inner 
portion  of  the  fibre,  thus  preserving  its  pliability  and  elasticity. 
Wool  grease  does  not  appear  to  be  a  simple  compound,  but  evi- 
dently consists  of  several  oils  and  wax-like  compounds.  Its 
chief  constituent  is  cholesterol,  which  appears  to  be  one  of  the 

*  The  statement  made  in  some  text-books  that  raw  wool  when  left  in  the 
greasy  condition  is  not  attacked  by  moths  is  erroneous.  The  personal  experi- 
ence of  the  author  has  proved  that  raw  wool  is  as  liable  to  the  depredations  of 
insects  as  washed  and  scoured  wool. 


WOOL  AND  HAIR  FIBRES  51 

higher  monatomic  alcohols,  and  is  not  a  glyceride.  Analysis 
shows  it  to  have  the  formula  C26H43OH.  It  is  a  solid  wax-like 
substance  which  very  readily  emulsifies  in  water.  Associated 
with  cholesterol  there  is  also  an  isomeric  body  called  isocholesterol. 
Besides  these  solid  waxes,  wool  grease  also  contains  two  fats 
which  have  been  studied  by  Chevreul  to  some  extent.  These 
are  described  as  follows: 

(a)  Stearerin,  a  neutral  solid  fat,  melting  at  60°  C.;  contains 
neither  nitrogen  nor  sulphur;  does  not  emulsify  with  boiling  water, 
but  emulsifies  without  saponification  when  boiled  with  caustic 
potash  and  water;  it  is  soluble  in  1000  parts  of  alcohol  at  15.5°  C. 

(b)  Elairerin,  a  neutral  fat  melting  at   15.5°  C.;    also  free 
from  nitrogen  and  sulphur;    it  emulsifies  with  boiling  waier, 
and  is  saponified  with  caustic  potash;   it  is  soluble  in  143  parts 
of  alcohol  at  15.5°  C. 

3.  Suint. — The  dried-up  perspiration  adhering  to  the  raw- 
wool  fibre  is  also  called  suint.     It  consists  principally  of  the 
potash  salts  of  various  fatty  acids,  and  it  is  soluble  in  water, 
wherein  it  differs  from  wool  grease.     On  extraction  with  water, 
suint  will  yield  a  dry  residue  of  about  140  to   180  Ibs.  for  1000 
Ibs.  of  raw  wool.     This  on  ignition  will  give  70  to  90  Ibs.  of 
potassium   carbonate  and   5   to  6  Ibs.   of  potassium  sulphate 
and  chloride,  so  that  the  amount  of  potash  salts  to  be  derived 
from  raw  unwashed  wool  may  be  taken  to  be  about  10  per 
cent  on  the  weight  of  wool.* 

4.  Ash  of  Wool   Fibre. — Besides  the  mineral  matter  exist- 
ing in  the  soluble  suint,  there  is  also  a  small  amount  of  mineral 
matter  which  appears  to  form  an  essential  constituent  of  the 
fibre  itself.     It  is  left  as  an  ash  when  wool  is  ignited,  and  amounts 
on  an  average  to  about  i  per  cent,  the  majority  of  which  is 
soluble  in  water  and  consists  of  the  alkaline  sulphates.     The 

*  Maumene   and   Rogelet  give  the  following  analysis  for  the  inorganic  con- 
stituents of  suint: 

Per  Cent. 

Potassium  carbonate 86 .  78 

Potassium  sulphate 6.18 

Potassium  chloride 2  . 83 

Silica,  phosphorus,  lime,  iron,  etc 4  •  21 


52  THE  TEXTILE   FIBRES 

following  analysis  by  Bowman  shows  the  typical  composition 
of  the  ash  of  Lincoln  wool: 

Per  Cent. 

Potassium  oxide 31.1 

Sodium  oxide 8.2 

Calcium  oxide 16.9 

Aluminium  oxide  1 
Ferric  oxide  / 

Silica 5.8 

Sulphuric  anhydride 20 . 5 

Carbonic  acid 4.2 

Phosphoric  acid .  •. • trace 

Chlorin trace 

Arsenic  appears  to  be  present  in  nearly  all  samples  of  wool, 
even  in  the  natural  state.  The  arsenic  is  generally  derived 
from  the  dips  to  which  the  sheep  are  subjected  even  the  wool 
from  a  lamb  whose  mother  has  been  dipped  a  considerable 
time  before  the  lamb's  birth  will  show  distinct  traces  of  arsenic. 
Thorpe  gives  the  following  figures  for  the  amounts  of  arsenic 
in  woolen  materials : 

Arsenious  Oxide 
Mgms.  per  Gram  of 
Material. 

Flannel  from  natural  wool o .  005-0 . 009 

White  Berlin  wool o . 037 

Cream  flannel o .  004 

Welsh  flannel o .  015 

Vest  wool  (undyed) o .  01 1 

Linen  (white) free 

Silk  (undyed) o .  ooi 

Wool  from  lamb  (mother  treated  with  arsenical  dip)  o .  0005 
Wool   from  lamb  (mother  dipped  shortly  before 

birth  of  the  lamb) o .  019 

Wool  from  ewe   (treated  with    carbolic    dip    15 

months  previously) o .  047 

5.  Coloring  Matter. — Sheep's  wool  is  nearly  always  white 
in  color,  though  sometimes  it  may  occur  in  the  natural  colors 
of  gray,  brown,  or  black.*  The  coloring  matter  in  wool  appears 

*  There  do  not  appear  to  be  any  laws  regulating  the  occurrence  of  black 
wool  in  sheep.  Beyond  the  difference  in  color  there  is  not  any  noticeable 
difference  in  structure  or  properties  between  black  wool  and  ordinary  wool. 
Climatic  conditions  do  not  seem  to  have  any  influence  on  the  production  of  black 
wool,  and  it  is  as  liable  to  occur  in  one  breed  as  in  another.  It  would  be  thought 
the  question  of  heredity  would  have  an  important  bearing  on  the  origin  of  black 
wool;  but  even  this  factor  appears  to  be  without  influence,  as  a  black  lamb  may 
have  both  parents  white,  both  black  or  one  white  and  one  black.  The  amount 


WOOL  AND   HAIR  FIBRES  53 

to  withstand  the  action  of  alkalies  and  acids,  though  it  is  not 
especially  permanent  toward  light.  It  appears  to  be  distributed 
in  the  fibre  in  quite  a  different  manner  from  that  of  the  artificially 
applied  dyes.  The  natural  coloring  matter  appears  to  be 
contained  particularly  in  the  cells  of  the  cortical  layer  and  the 
marrow  in  a  granular  form,  and  to  occur  to  a  greater  extent 
in  the  medullary  than  in  the  cortical  cells.  In  fibres  which 
are  only  slightly  colored  the  walls  of  the  cells  are  almost  colorless ; 
though  when  the  fibre  becomes  very  strongly  colored  the  cell- 
walls  also  appear  to  be  impregnated  with  the  coloring  matter. 
In  wools  which  have  been  dyed,  however,  the  cell-walls  are 
nearly  always  uniformly  colored,  in  consequence  of  which  the 
medulla  of  the  fibre  becomes  less  pronounced;  whereas,  with 
naturally  colored  wools,  the  medulla  is  usually  rendered  more 
distinct  through  the  deposit  of  coloring  matter. 

6.  Chemical  Constitution  of  Wool;  Keratin.  The  wool 
fibre  has  been  found  to  consist  of  five  chemical  elements ;  namely, 
carbon,  hydrogen,  oxygen,  nitrogen,  and  sulphur.  Nitrogen 
is  an  ingredient  common  to  both  wool  and  silk,  but  sulphur 
is  distinctly  characteristic  of  wool  and  hair  fibres. 

In  its  chemical  nature  wool  is  classed  as  a  proteoid,  known 
as  keratin.  As  its  constituents  are  not  rigidly  constant  in  their 
proportions,we  cannot  assign  to  wool  a  definite  chemical  formula.* 

of  black  wool  appearing  in  the  American  domestic  trade  is  about  3  to  5  per  cent 
of  the  total  clip.  It  is  used  almost  exclusively  in  the  undyed  condition  for  the 
production  of  gray  mixes  for  hosiery  and  underwear. 

*  Keratin,  free  from  ash,  water,  and  melanin,  on  hydrolysis  gave  the  follow- 
ing amounts  of  monamino-acids: 

Keratin  from  Keratin  from 

Horsehair,  Goose-feathers, 

Per  Cent.  Per  Cent. 

Glycin 4.7  2.6 

Alanin 1.5  1.8 

Amino-valeric  acid 0.9  0.5 

Leucin 7.1  8.0 

Pyrolidin-2-carboxylic  acid 3.4  3.5 

Aspartic  acid 0.3  i .  i 

Glutaminic  acid 3.7  2.3 

Tyrosin 3.2  3.6 

Serin 0.6  0.4 

(Abderhalden,  Zeit.  physiol.  Chem.,  vol.  46,  p.  31.) 
(Note  continued  on  next  page.) 


THE   TEXTILE   FIBRES 


On  an  average,  its  composition  may  be  taken  as  follows: 

Per  Cent. 

Carbon 50 

Hydrogen 7 

Oxygen 26-22 

Nitrogen 15-17 

Sulphur 2-4 

Bowman  gives  the  following  analyses  of  four  different  grades 
of  English  wool: 


Constituent. 

Lincoln 
Wool. 

Irish 
Wool. 

Northumber- 
land Wool. 

Southdown 
Wool. 

Carbon 

<2    O 

4.0  8 

so  8 

PI   •? 

Hydrogen  

6.9 

7-  2 

7    2 

6  9 

Nitrogen 

18  i 

10    I 

18  <; 

17  8 

Oxygen  

20.3 

19.9 

21  .  2 

2O.  2 

Sulphur         

2  .  5 

"?  -O 

2    3 

7     8 

Loss 

O    2 

I    O 

These  analyses  were  made  of  wool  which  had  been  purified  by 
extraction  with  water,  alcohol,  and  ether. 

The  wool  fibre  as  a  whole  does  not  appear  to  be  a  homoge- 
neous chemical  compound ;  instead  of  being  a  simple  molecular 
body  to  which  a  definite  formula  might  be  given,  it  is  doubtless 
composed  of  several  chemically  distinct  substances.  This  is 
evidenced  by  the  fact  that  the  proximate  constituents  of  wool 
are  by  no  means  constant  in  their  amount;  furthermore,  cer- 
tain of  its  constituents  are  in  part  removed  by  simply  boiling 
the  fibre  in  water  without  a  structural  disorganization  taking 
place.  The  sulphur  content  is  especially  liable  to  fluctuation, 
and  is  the  most  readily  removed  of  the  chemical  elements  of 
which  the  fibre  is  composed;  in  fact,  so  easily  is  some  of  the 

According  to  the  tables  of  Cohnheim,  the  percentages  of  known  constituents 
in  the  keratin  from  hair  are  as  follows: 

Per  Cent. 

Leucin 14 

Glutaminic  acid 12 

Aspartic  acid not  determined 

Cystin 13-92 

Tyrosin 3 

Ammonia large  amount 


WOOL  AND  HAIR   FIBRES  55 

sulphur  removed  as  such  by  various  solvents,  that  it  would 
seem  to  indicate  that  this  constituent  existed  in  wool  either  in 
the  free  condition  or  in  a  compound  of  exceedingly  unstable 
character. 

Schuetzenberger,  by  decomposing  pure  wool  fibre  by  heat- 
ing with  a  solution  of  barium  hydrate  at  170°  C.,  obtained 
the  following  decomposition  products: 

Per  Cent. 

Nitrogen  (evolved  as  ammonia) 5.25 

Carbonic  acid  (separated  as  barium  carbonate) 4.  27 

Oxalic  acid  (separated  as  barium  oxalate) 5-72 

Acetic  acid  (by  distillation  and  titration) 3 .  20 

Pyrrol  and  volatile  products i  to  i .  50 

j-C   47-85 

Proximate  composition  of  fixed  residue,  containing  i  H     7 . 69 
leucin,  tyrosin,  and  other  volatile  products |  N    12 .63 

10  31.18 

Williams  has  shown  that  by  distilling  wool  with  strong 
caustic  potash  a  large  amount  of  ammonia  was  obtained  in  the 
distillate,  together  with  butylamin  and  amylamin.  Dry  dis- 
tillation of  wool  yields  an  oil  of  a  very  disagreeable  odor,  probably 
consisting  of  various  sulphuretted  bases;  also  a  considerable 
amount  of  pyrol  and  hydrogen  sulphide  gas,  together  with  a 
small  amount  of  carbon  disulphide,  and  traces  of  various  oily 
bases. 

7.  Nitrogen  in  Wool;  Lanuginic  Acid.— The  presence  of 
nitrogen  in  wool  is  readily  made  evident  by  simply  burning 
a  small  sample  of  the  fibre,  when  the  characteristic  empyreumatic 
odor  of  nitrogenous  animal  matter  will  be  observed.  By  heating 
wool  in  a  small  combustion  test- tube  it  will  be  noticed  that 
ammonia  is  among  the  gaseous  products  evolved,  and  can  be 
tested  for  in  the  usual  manner. 

Schuetzenberger  has  shown  that  the  products  of  the  hydrolysis 
of  wool  by  baryta-water  are  analogous  to  those  of  albuminoids 
containing  amino  groups;  the  experiments  of.Prud'homme  *  and 
Flick  also  indicate  the  presence  of  imino  rather  than  amino 
groups  in  wool.  The  fact  that  wool  absorbs  nitrous  acid,  and 

*  Rev.  Gen.  Mat.  Col.,  1898,  p.  209. 


56  THE  TEXTILE  FIBRES 

combines  with  phenols,  which  is  supposed  to  indicate  the  pres- 
ence of  amino  groups,  may  be  explained  by  the  formation  of 
nitrosamines  with  the  imino  groups,  which  would  also  yield 
colored  derivatives  with  phenols.* 

The  amino  acid  of  keratin  has  received  the  name  of  lanuginic 
acid,  and  has  been  prepared  by  dissolving  purified  wool  in  a 
strong  solution  of  barium  hydrate,  precipitating  the  barium 
by  means  of  carbon  dioxide,  and  after  filtering,  treating  the 
liquid  with  lead  acetate,  whereby  the  lead  salt  is  obtained. 
This  is  decomposed  by  means  of  hydrogen  sulphide,  and  the 
lanuginic  acid  obtained,  after  evaporation,  as  a  dirty-yellow 
substance.  Its  solution  in  water  yields  colored  lakes  with  the 
acid  and  basic  dyestuffs,  and  also  with  the  various  mordants,  f 

According  to  Knecht,  lanuginic  acid  possesses  the  following 
properties:  It  is  soluble  in  water,  sparingly  so  in  alcohol,  and 
insoluble  in  ether.  Its  aqueous  solution  yields  highly  colored 
precipitates  with  the  acid  and  basic  dyestuffs;  tannic  acid  and 
bichromate  of  potash  also  give  precipitates.  The  following 
mordants  in  the  presence  of  sodium  acetate  also  give  precipitates: 
Alum,  stannous  chloride,  copper  sulphate,  ferric  chloride, 
ferrous  sulphate,  chrome  alum,  silver  nitrate,  and  platinum 
chloride.  Lanuginic  acid  exhibits  all  the  properties  of  a  pro- 
teoid,  and  may  therefore  be  classed  among  the  albuminoids; 
it  is  soluble  in  water  at  all  temperatures,  and  its  solution  is  not 
coagulated.  With  •  Millon's  reagent  and  with  the  double  com- 
pound of  phosphoric  and  tungstic  acids,  it  shows  the  char- 
acteristic albuminoid  reactions.  Knecht  recommends  the  use 
of  a  solution  of  wool  in  barium  hydrate  for  the  purpose  of 
animalizing  vegetable  fibres.  Cotton  so  treated  is  capable 
of  being  dyed  with  acid  and  basic  dyestuffs. 

When  heated  to  100°  C.,  lanuginic  acid  becomes  soft  and 

*  Saget  (Monit.  Sclent.,  1910,  p.  80)  supports  the  theory  that  wool  contains 
amino,  imino,  and  carboxyl  groups,  claiming  that  this  constitution  is  required 
to  explain  why  wool  mordanted  with  tannate  of  tin  loses  its  affinity  for  acid  dyes. 

f  Champion  (Compt.  rend.,  vol.  72,  p.  330)  gives  the  formula  of  lanuginic 
acid  as  C19H3oN5Oio,  but  Knecht  and  Appelyard  (Jour.  Soc.  Dyers  6*  Col.,  1889, 
p.  71)  reject  this  formula,  as  they  show  that  the  compound  contains  about  3  per 
cent  of  sulphur. 


WOOL  AND   HAIR  FIBRES  57 

plastic,  and  the  majority  of  its  colored  lakes  also  melt  at  this 
temperature.  Knecht  gives  the  following  analysis  of  lanuginic 
acid: 

Per  Cent. 

Carbon 41.61 

Hydrogen 7.31 

Nitrogen 10.26 

Sulphur 3.35 

Oxygen 31-44 


93-97 

Though  lanuginic  acid  contains  a  notable  amount  of  sulphur  in 
its  composition,  it  is  not  blackened  by  treatment  with  sodium 
plumbite. 

8.  Sulphur  in  Wool. — The  presence  of  sulphur  in  wool 
can  be  shown  by  dissolving  a  sample  of  the  fibre  in  a  solution 
of  sodium  plumbite  (obtained  by  dissolving  lead  oxide  in  sodium 
hydrate),  when  a  brown  coloration  will  be  observed,  due  to  the 
formation  of  lead  sulphide.  On  adding  hydrochloric  acid  to 
the  solution  and  heating,  the  odor  of  sulphuretted  hydrogen 
will  be  distinctly  noticed.  The  application  of  this  test  to 
show  the  presence  of  sulphur  in  wool  is  sufficient  to  discriminate 
chemically  between  that  fibre  and  those  consisting  of  silk  or 
cotton,  and  also  to  detect  wool  in  admixture  with  other  fibres. 
The  older  methods  of  hair-dyeing  were  based  on  this  same 
reaction,  solutions  of  soluble  lead  salts,  such  as  sugar  of  lead, 
being  applied  to  the  hair,  with  the  result  that  lead  sulphide 
would  be  formed  and  cause  a  dark  brown  coloration.  The  use 
of  such  preparations,  however,  is  dangerous,  as  they  are  liable 
to  cause  lead-poisoning. 

The  presence  of  sulphur  in  wool  may  at  times  be  the  cause 
of  certain  defects  in  the  dyeing  process.  In  neutral  or  alkaline 
baths,  if  lead  is  present,  the  color  obtained  on  the  fibre  will  be 
more  or  less  affected  by  the  lead  sulphide  formed  on  the  wool, 
and  serious  stains  may  be  the  result.  The  presence  of  sul- 
phuric acid,  however,  prevents  this,  and  no  staining  of  the 
fibre  takes  place.  Stains  are  sometimes  produced  when  wool 
is  mordanted  with  stannous  chloride,  as  in  the  dyeing  of  cochineal 


58  THE  TEXTILE  FIBRES 

scarlets,  due  to  the  formation  of  stannous  sulphide.  Occa- 
sionally woolen  printed  goods  exhibit  brownish  stains  on  the 
white  or  light-colored  portions  after  being  steamed.  These 
may  be  due  to  slight  traces  of  copper  or  lead  being  deposited 
on  the  cloth  during  its  manipulation  and  passage  through  the 
machines,  and  these  metals  when  the  wool  is  steamed  form 
dark  colored  sulphides  which  cause  the  stains.  By  locally 
applying  a  weak  solution  of  hydrogen  peroxide  such  discolora- 
tions  may  be  removed  without  injury  to  the  printed  color. 

Chevreul  recognized  the  fact  that  in  certain  dyeing  opera- 
tions it  was  necessary  to  remove  the  sulphur  from  wool  as  far 
as  possible  in  order  to  obtain  the  best  results.  He  accomplished 
this  by  steeping  the  wool  in  milk  of  lime  and  afterward  in  a 
weak  bath  of  hydrochloric  acid,  and  finally  washing. 

The  amount  of  sulphur  existing  in  wool  does  not  appear  to 
be  a  very  constant  factor,  but  varies  in  different  samples  of 
wool  from  0.8  to  4  per  cent.*  The  manner  in  which  the  sul- 
phur exists  in  the  molecular  structure  of  the  fibre  is  by  no  means 
clear,  as  the  majority  of  it  is  readily  removed  without  any 
apparent  structural  modification  of  the  fibre  itself.  According 
to  Chevreul  the  amount  of  sulphur  in  wool  was  reduced  to 
0.46  per  cent  by  several  treatments  with  lime-water.  Treat- 
ment with  a  concentrated  solution  of  caustic  soda  in  such  a 
manner  as  not  to  disintegrate  the  fibre  (see  p.  66)  will  remove 
as  much  as  84.5  per  cent  of  the  sulphur  originally  present  in 
the  wool.  On  a  sample  of  wool  containing  3.42  per  cent  of 
sulphur,  treatment  in  this  manner  left  only  0.53  per  cent  of 
sulphur  in  the  fibre.  This  would  appear  to  indicate  that  the 
sulphur  is  not  a  structural  constituent  of  the  wool  fibre,  f  The 

*  Wool  is  similar  to  other  albuminoids  in  that  it  contains  a  relatively  small 
though  a  widely  fluctuating  amount  of  sulphur.  The  following  sulphur  com- 
pounds have  been  isolated  from  the  decomposition  products  of  the  albuminoids: 
Cystin,  cystein,  thiolactic  acid,  thioglycollic  acid,  ethyl  sulphide,  ethyl  mercap- 
tan,  sulphuretted  hydrogen,  and  diethyl-thetin. 

t  The  presence  of  sulphuric  or  sulphurous  acids  has  formerly  never  been 
observed  in  the  decomposition  products  of  albuminoids  and  this  led  to  the  opinion 
that  the  albumin  molecule  did  not  contain  sulphur  in  combination  with  oxygen. 
Raikow  (Chem.  Zeil.,  1905,  p.  900),  however,  finds  that  when  purified  un- 


WOOL  AND  HAIR  FIBRES  59 

fact,  however,  that  the  sulphur  present  is  not  all  removed 
by  even  such  severe  treatment  as  described  would  also  serve 
to  indicate  that  this  element  may  exist  in  wool  in  two  forms, 
the  one  an  ultimate  constituent  of  the  fibre,  and  the  other, 
and  major  part,  as  a  more  loosely  combined  compound.  The 
fact  that  the  amount  of  sulphur  naturally  present  in  wool  is 
by  no  means  constant  would  also  tend  to  support  this  view; 
as  would  also  the  fact  that  the  major  portion  of  the  sulphur  is 
so  readily  split  off  to  form  metallic  sulphides.  On  dissolving 
wool  in  boLing  caustic  soda,  it  does  not  appear  that  all  of  the 
sulphur  is  converted  into  sodium  sulphide,  as  only  about  80 
per  cent  of  it  can  be  obtained  as  hydrogen  sulphide  when  the 
caustic  soda  solution  is  treated  with  acid.  Probably  the  remain- 
der of  the  sulphur  exists  in  the  wool  as  a  sulphonic  acid.,  or  some 
compound  of  a  similar  nature.* 

9.  Chemical  Reactions  of  Wool;  with  Water. — Though 
wool  is  insoluble  in  cold  water  and  also  in  hot  water  under 
ordinary  conditions,  still  the  continued  action  of  boiling  water 
appears  to  decompose  the  wool  fibre  to  a  certain  extent,  as 
both  ammonia  and  hydrogen  sulphide  may  be  detected  in  the 
gases  evolved.!  The  soluble  decomposition  products  of  wool 

bleached  wool  is  treated  with  phosphoric  acid  considerable  quantities  of  sul- 
phurous acid  are  evolved. 

*  According  to  Prud'homme  (Rev.  Gen.  Mat.  Col.,  1898,  p.  209)  the  sulphur 
in  the  wool  is  probably  combined  either  as 


N-CnH2n-CO  or 


N-C«H2«-CS. 


It  is  also  contained  in  the  natural  coloring  matter  of  the  wool. 

f  Herz  and  Barraclough  (Jour.  Soc.  Dyers  and  Color.,  1909,  p.  274)  point  out 
that  wool  on  boiling  in  water  yields  a  soluble  substance  which  gives  the  tannin 
and  biuret  reactions  for  gelatin.  Solutions  of  lead  acetate,  however,  precipi- 
tate wool  gelatin  from  solution,  but  have  no  effect  on  solutions  of  ordinary  glue 
or  gelatin.  Further  experiments  seem  to  indicate  that  wool  gelatin  consists  of 
three  substances:  (i)  One  which  is  not  precipitated  by  Night  Blue,  but  which 
is  precipitated  by  the  tannin-salt  reagent  (a  filtered  mixture  of  100  c.c.  of  a  2  per 
cent  solution  of  tannin  and  100  c.c.  of  a  saturated  solution  of  salt);  (2)  one  which 
is  precipitated  by  Night  Blue,  and  which  goes  into  solution  when  this  precipi- 


60  THE  TEXTILE  FIBRES 

produced  by  boiling  with  water  show  all  the  characteristic 
properties  of  the  peptones.  Suida  suggests  that  this  action 
of  boiling  water  on  wool  may  account  for  the  lack  of  fastness 
to  rubbing  often  noticed  with  basic  colors  on  wool. 

By  heating  wool  to  a  temperature  of  130°  C.  with  water 
under  pressure,  the  fibre  appears  to  become  completely  dis- 
organized, and  on  drying  may  be  rubbed  into  a  fine  powder. 
At  higher  temperatures  the  fibre  is  completely  dissolved.  Based 
on  this  fact,  Knecht  has  proposed  a  method  for  the  "  carbon- 
ization" of  mixed  woolen  and  silk  goods,  for  the  purpose  of 
recovering  the  silk,  as  the  latter  is  not  materially  affected  by 
this  treatment.* 

10.  Acid  and  Basic  Nature  of  Wool. — In  its  chemical  reac- 
tions wool  appears  to  exhibit  the  characteristics  both  of  an 
acid  and  a  base,  and  no  doubt  it  contains  an  amino  acid  in  its 
composition.  The  presence  of  an  amino  group  is  evidenced 
by  the  formation  of  ammonia  as  one  of  the  decomposition  prod- 
ucts of  wool,  also  by  the  strong  affinity  of  wool  for  the  acid 
dyestuffs,  or  even  of  its  ability  to  combine  with  acids  in 
general. 

The  acid  nature  of  wool  accounts  for  the  possibility  of  the 
formation  of  compounds  of  the  fibre  with  various  metallic 
salts,  alkalies,  and  metallic  oxides,  and  therefore  for  the  dif- 
ference in  behavior  in  dyeing  between  wools  which  have  been 
scoured  with  alkaline  carbonates  or  treated  with  metallic  salts 
or  hard  water,  and  wool  which  has  not  had  its  acid  groups 
saturated  in  this  way.  It  also  accounts  for  the  fact  that  dif- 
ferent wools  require  the  addition  of  different  amounts  of  acid 
to  the  dye-bath  to  give  the  same  effect.f 

The  coefficient  of  acidity,  which  is  a  figure  meaning  the 
number  of  milligrams  of  caustic  potash  neutralized  by  one  gram 

tate  is  decomposed  with  barium  hydrate,  and  after  removal  of  excess  of  baiium 
hydrate  is  again  capable  of  precipitation  by  either  Night  Blue  or  tannin-salt;  (3) 
one  which  is  precipitated  by  Night  Blue,  but  on  decomposing  the  precipitate 
with  barium  hydrate,  remains  insoluble. 

*This  method,  though  theoretically  possible,  does  not  appear  to  have  any 
practical  value. 

t  See  experiments  of  Gelmo  and  Suida,  Ber.  Akad.  Wissenschaften,M3Ly,  1905. 


WOOL  AND  HAIR  FIBRES  61 

of  substance,  has  been  determined  for  wool,  together  with  a 
number  of  other  albuminoids,  as  follows: 

Wool 57 .o  Albumin 20.9 

Silk 143-0  Gelatin 28 . 4 

Globulin 101 . 5 

Although  the  amount  of  alkali  absorbed  and  neutralized  by 
wool  may  be  thus  quantitatively  determined,  the  amount  of 
acid  absorbed  cannot  be  so  obtained,  as  wool,  though  it  absorbs 
acids,  apparently  does  not  neutralize  them. 

Wool  which  has  been  treated  with  a  dilute  solution  of  caustic 
alkali  apparently  shows  no  difference  from  untreated  wool 
in  its  dyeing  properties  with  respect  to  acid  and  basic  dyes. 
That  alkali  has  been  absorbed  by  the  wool,  however,  is  shown 
by  the  fact  that  it  has  an  increased  attraction  for  such  dyes  as 
Benzopurpurin,  etc.,  which  only  dye  wool  from  a  slightly 
alkaline  bath. 

By  treatment  with  concentrated  solutions  of  caustic  soda 
(80°  Tw.)  wool  absorbs  about  50  per  cent  of  its  weight  of  sodium 
hydrate  from  solution.  Nor  can  this  alkali  be  totally  removed 
from  the  wool  by  subsequent  washing  with  water  alone,  but 
requires  a  treatment  with  acid  for  complete  neutralization. 
Wool  so  treated  exhibits  a  lessened  affinity  for  basic  dyes, 
showing  a  probable  neutralization  to  a  greater  or  lesser  extent 
of  its  acid  component. 

Vignon  *  has  experimented  on  the  amount  of  heat  disen- 
gaged by  treating  wool  with  different  acids  and  alkalies,  with 
the  following  results,  using  100  grams  of  unbleached  wool: 

Reagent.  Calories  Liberated. 

Potassium  hydrate  (normal) 24 . 50 

Sodium  hydrate  (normal) 24 . 30 

Hydrochloric  acid  (normal) 20.05 

Sulphuric  acid  (normal) 20 . 90 

These  figures  are  interesting  in  indicating  the  relative  acidity 
and  alkalinity  of  the  wool  fibre. 

ii.  Action  of  Acids  on  Wool. — When  treated  with  dilute  acids, 
the  wool  fibre  does  not  appear  to  undergo  any  appreciable 

*  Compt.  rend.,  1890,  No.  17. 


62 


THE  TEXTILE   FIBRES 


change;  although,  from  the  fact  that  acids  are  very  readily 
absorbed  by  wool  and  very  tenaciously  held  by  it,  there  is  reason 
to  believe  that  some  chemical  combination  takes  place  between 
the  fibre  and  the  acid.  It  can  be  shown,  for  example,  that 
if  wool  be  treated  with  dilute  sulphuric  acid,  all  of  the  acid 
cannot  again  be  extracted  by  boiling  in  water  until  the  wash- 
. waters  are  perfectly  neutral;  *  and  wool  thus  prepared  has 
the  power  of  combining  with  the  various  acid  colors  without 
the  necessity  of  adding  any  acid  to  the  dye-bath.  Wool  that 
has  been  treated  with  warm  dilute  solutions  of  sulphuric  acid 
not  only  shows  an  increased  affinity  for  acid  colors,  but  also 
a  decreased  affinity  for  basic  colors.  Treatment  of  wool 
with  cold  aqueous  or  alcoholic  solutions  of  sulphuric  acid, 
however,  followed  by  washing  with  cold  water,  appears  to 
diminish  the  affinity  of  the  fibre  for  acid  colors,  from  which  it 
is  concluded  that  the  acid  is  fixed  in  a  somewhat  different  way 
than  when  the  wool  is  heated  with  the  acid  solution.  Acidified 
wool  also  shows  an  increased  power  of  dyeing  alizarin  colors 
direct.  Other  acids  have  about  the  same  effect  on  wool  as  sul- 
phuric acid,  only  in  the  case  of  acetic  acid  it  is  necessary  to  add 
the  acid  directly  to  the  dye-bath  in  order  to  hinder  the  fixation 
of  basic  colors  or  increase  the  absorption  of  acid  colors,  f  It 
is  also  true  that  if  wool  which  has  been  treated  with  sulphuric 
acid  is  boiled  in  water,  ammonium  sulphate  is  to  be  found  in 
the  solution,  showing  that  some  chemical  action  has  probably 
taken  place  between  the  acid  and  some  basic  constituent  of 

*  The  following  table  shows  the  relative  absorption  of  sulphuric  acid  from  its 
solutions  by  wool  (Mills  and  Takamine) : 


Per  Cent  Acid 
Used. 

Per  Cent  Left  in 
Solution. 

Per  Cent  Absorbed 
by  Wool. 

2i 

0.38 

2.12 

5 

2.1? 

2.83 

10 

6-37 

3.63 

20 

15-87 

4-13 

40 

55  -18 

4.82 

t  See  Gelmo  and  Suida,  Ber.  Akad.  Wissenschaften,  May,  1905. 


WOOL  AND  HAIR  FIBRES 


63 


the  wool  fibre.  Hydrochloric  acid  acts  much  in  the  same  manner 
as  sulphuric  acid,  although  the  amount  permanently  absorbed 
by  the  fibre  is  quite  small,  most  of  the  acid  being  removed  by 
boiling  water.*  Chromic  acid  is  also  absorbed  in  like  manner, 
-and  no  doubt  the  usefulness  of  bichromates  as  mordants  for 
wool  depends  somewhat  on  the  chemical  combination  between 
the  fibre  and  the  chromic  acid.  With  nitric  acid  wool  behaves 
somewhat  differently,  for  unless  the  acid  be  very  dilute  and  the 
temperature  low,  the  fibre  will  assume  a  yellow  color,  which 
is  probably  due  to  the  formation  of  xanthoproteic  acid.  For- 
merly this  yellow  color  was  supposed  to  be  due  to  the  formation 
of  picric  acid,  but  this  view  is  erroneous.  Nitric  acid  has  a  similar 

*  Mills  and  Takamine  (Jour.  Chem.  Soc.,  1883,  p.   144)  have  studied  the 
relative  absorption  of  mixed  acids  on  the  fibres,  as  follows: 


Ratio. 
H2S04  :  HC1 

Wool. 

Silk. 

H2SO4 

HC1 

H2S04 

HC1 

i  :  i 

5-0 

32-5 

6.6 

0.87 

i  :  2 
i  :  4 

K.  -3 

16.6 

25-5 
18.4 

5-0 
4.0 

2-5 

3-5 

The  rate  of  absorption  of  these  acids  when  present  in  the  ratio  of  H2SO4  :  4HC1 
was  as  follows: 


Fibre. 

H2S04 

HC1 

Wool            .... 

IOO 

170-6 

Silk  

100 

175-0 

The  maximum  absorption  for  silk  and  cotton  was: 


Reagent. 

Cotton. 

Silk. 

H2SO4  

I 

2.6 

HC1 

I 

2    2 

NaOH 

I 

2    2 

i 

When  wool  is  treated  with  weak  reagents  separately  in  the  proportion 
HC1  :  NaOH,  the  absorption  is  in  the  ratio  2HC1  :  sNaOH.  With  silk  and 
cotton  the  ratio  is  HCl  :  loNaOH. 


64  THE  TEXTILE  FIBRES 

effect  on  the  skin,  the  yellow  stains  which  it  produces  being  a 
subject  of  common  experience.  If  the  strength  of  the  acid 
is  below  4°  Tw.,  the  yellow  coloration  on  wool  is  not  very  marked, 
and  in  this  manner  nitric  acid  has  been  largely  employed  as  a 
stripping  agent,  especially  for  shoddies. 

Richards  *  has  shown  that  by  the  action  of  nitrous  acid, 
wool  is  diazotized  in  a  manner  similar  to  an  amino  compound, 
and  may  be  developed  subsequently  in  an  alkaline  solution  of  a 
phenol,  giving  rise  to  quite  a  variety  of  shades.  When  wool 
is  treated  in  the  dark  with  an  acid  solution  of  sodium  nitrite 
(6  per  cent)  it  quickly  acquires  a  pale-yellow  color,  rapidly 
changing  on  exposure  to  light.  Wool  prepared  in  this  manner 
is  turned  brown  by  boiling  water,  and  caustic  soda  effects  the 
same  change,  the  color  becoming  yellow  again  on  treatment 
with  acids.  Stannous  chloride  in  a  warm  solution  discharges 
the  brown  color.  Diazotized  wool  appears  to  have  an  increased 
attraction  for  basic  dyes  and  a  lessened  affinity  for  the  acid 
dyes.  Exposure  to  light  bleaches  diazotized  wool,  which  is 
then  turned  orange  by  alkalies,  and  not  brown.  The  follow- 
ing colors  may  be  obtained  by  treating  diazotized  wool  with 
various  phenols  in  alkaline  solution: 

Phenol.  Color.  Reaction  withH2SO4. 

Resorcin  Orange  Pale  red 

Orcin  Orange  Pale  red 

Pyrogallol  Yellowish  brown  Orange 

Phloroglucin  Bordeaux  No  change 

a-Naphthol  Red  Black 

p-Naphthol  Red  Pale  red 

When  dyed  in  connection  with  metallic  mordants,  these 
phenol  colors  are  fast  to  light,  fulling,  acids,,  and  boiling  water. 
Tin  mordants  give  yellow  and  orange  shades,  aluminium  orange, 
iron  dark  browns  and  olive  browns,  chromium  and  copper 
garnet.  Wool  treated  with  nitrous  acid  acquires  a  harsh  feel 
and  is  non-hygroscopic.  It  also  appears  to  have  an  increased 
affinity  for  basic  dyes.f 

*  Jour,  Soc.  Chem.  Ind.,  1888,  p.  841. 
t  Flick,  Bull.  Soc.  Ind.  Mul.,  1899,  p.  221. 


WOOL  AND   HAIR  FIBRES  65 

The  acid  number  of  diazotized  wool  is  169,  and  its  iodin 
number  4.7,  whereas  untreated  wool  has  the  numbers  88  and 
18.4  respectively.  Diazotized  wool  also  appears  to  contain 
less  nitrogen  than  ordinary  wool.* 

In  common  with  most  other  organic  substances,  wool  is 
totally  destroyed  by  the  action  of  concentrated  mineral  acids. 
On  treatment  with  cold  concentrated  sulphuric  acid  for  a  short 
time  wool  is  not  seriously  disintegrated;  the  fibre,  however, 
suffers  a  change  in  that  it  loses  all  affinity  for  acid  dyes,  while 
it  strongly  attracts  basic  dyes.f 

With  organic  acids,  wool  is  usually  reactive,  readily  absorb- 
ing oxalic,  lactic,  tartaric,  acetic,  etc.,  acids.  Tannic  acid, 
however,  is  an  exception,  and  is  not  absorbed  to  any  extent 
by  the  fibre.  But  if  wool  is  treated  in  a  boiling  solution  of  tannic 
acid  and  the  latter  fixed  in  the  fibre  by  a  subsequent  treatment 
in  a  solution  of  tartaric  emetic,  stannous  chloride,  or  other 
suitable  metallic  salt,  it  will  be  found  that  the  fibre  becomes 
altered  in  such  manner  that  it  no  longer  exhibits  its  normal 
affinity  toward  acid,  substantive,  and  mordant  dyes.  Toward 
basic  dyes,  however,  the  affinity  of  the  wool  becomes  con- 
siderably increased  by  reason  of  the  presence  of  tannin.  J 

12.  Action  of  Alkalies  on  Wool. — Although  so  resistant  to 
the  action  of  acids,  on  the  other  hand,  wool  is  quite  sensitive 
to  alkalies;  so  much  so,  in  fact,  that  a  five  per  cent  solution 
of  caustic  soda  at  a  boiling  temperature  will  completely  dissolve 
wool  in  a  few  minutes.  From  this  fact  it  is  easy  to  understand 
why  soaps,  and  scouring  and  fulling  agents  in  general,  should 
be  free  from  appreciable  amounts  of  caustic  alkalies.  The 


*  Lidow,  Chem.  Centr.,  1901,  p.  703. 

f  Text.  Rec.,  vol.  22,  p.  229. 

J  This  reaction  is  the  basis  of  applying  the  so-called  "resist"  process  to  the 
dyeing  of  wool.  Worsted  or  woolen  yarn  is  treated  with  a  solution  of  tannic 
acid,  and  then  with  one  of  stannous  chloride.  The  treated  yarn  is  then  woven 
with  untreated  yarn,  and  the  fabric  dyed  in  the  piece  with  various  colors  which 
have  little  or  no  affinity  for  the  treated  fibre,  but  show  their  normal  dyeing 
properties  toward  the  untreated  wool.  Such  dyes  are  known  as  "resist"  colors 
for  this  process.  A  number  of  the  one-bath  or  after-chromed  alizarin  or  mordant 
dyes  are  suitable  for  this  purpose. 


66  THE  TEXTILE   FIBRES 

weaker  alkaline  salts,  such  as  the  carbonates,  soaps,  etc.,  are 
not  so  destructive  in  their  action,  and  when  employed  at  mod- 
erate temperatures  they  are  not  regarded  as  deleterious,  and 
are  largely  used  in  scouring  and  fulling.  With  respect  to  the 
amount  of  caustic  alkali  necessary  to  decompose  wool,  Knecht 
found  that  on  boiling  wool  for  three  hours  with  3  per  cent 
(on  the  weight  of  the  wool)  of  caustic  soda  the  fibre  was  not 
disintegrated,  but  on  increasing  the  amount  to  6  per  cent 
complete  disintegration  took  place  and  the  wool  was  almost 
entirely  dissolved. 

The  .action  of  concentrated  solutions  of  caustic  alkalies 
on  wool  is  a  rather  peculiar  one.*  Solutions  of  caustic  soda  of 
a  strength  below  75°  Tw.  will  rapidly  disintegrate  the  fibre, 
but  with  solutions  of  75°-ioo°  Tw.  the  fibre  is  no  longer  dis- 
integrated, but,  on  the  other  hand,  increases  from  25  to  35  per 
cent  in  tensile  strength,  becomes  quite  white  in  appearance, 
and  acquires  a  high  lustre  and  a  silky  scroop.  The  maximum 
effect  is  obtained  by  using  a  caustic  soda  solution  of  80°  Tw. 
and  keeping  the  temperature  below  20°  C.f  The  duration 
of  the  treatment  should  not  be  more  than  five  minutes.  J  The 
addition  of  glycerol  to  the  solution  of  caustic  soda  renders  the 
action  of  the  alkali  more  effective.  Wool  treated  in  this  manner 
may  be  said  to  be  "  mercerized,"  though  the  action  of  the 
caustic  soda  in  this  case  is  not  quite  analogous  to  that  in  the 
mercerization  of  cotton.  From  the  decrease  in  the  density 
of  the  caustic  soda  solutions  employed,  it  has  been  shown  that 
the  wool  absorbs  a  considerable  amount  of  sodium  hydrate  from 
solution.  Whether  this  alkali  is  held  by  the  wool  in  true  chemi- 
cal combination  has  not  been  ascertained.  The  treated  wool 

*  Kertesz,  Farber-Zeit.,  vol.  9.  pp.  35-36;    Buntrock,  ibid.,  vol.  9,  pp.  69-71. 

f  Matthews.  Jour.  Soc.  Chem.  Ind.,  1902,  p.  685. 

t  Crepon  effects  may  be  obtained  on  union  goods  (of  wool  and  cotton  yarns) 
by  the  action  of  strong  caustic  soda,  which  exercises  a  strong  shrinking  action  on 
the  cotton  while  not  materially  affecting  the  wool.  A  caustic  soda  solution 
of  about  50°  Tw.,  is  used  at  a  temperature  under  50°  F.,  and  the  time  of  immer- 
sion should  not  be  more  than  one-third  minute.  Excess  of  caustic  is  then 
squeezed  out,  and  the  goods  are  neutralized  by  passage  through  a  fairly  strong 
(30  grams  of  sulphuric  acid  per  litre)  but  cold  acid  bath.  By  suitable  weaving 
various  pattern  effects  may  be  obtained. 


WOOL  AND  HAIR  FIBRES  67 

contains  but  a  small  amount  of  sulphur  compared  with  that 
present  in  the  original  fibre  (see  p.  57);  analysis,  in  fact,  shows 
that  only  about  15  per  cent  of  the  original  sulphur  remains 
in  the  mercerized  wool.  The  dyeing  qualities  of  the  latter  are 
also  different  from  the  original  fibre  in  that  it  absorbs  more 
dyestuff  from  solution  and  hence  yields  heavier  shades. 
Quantitative  tests  have  shown  that  the  increase  in  the  absorp- 
tion of  dyestuff  s  is  as  follows: 


Class  of  Dyestuff, 

Basic  .....................  .....................   12.5 

Acid  ...........................................   20  .  o 

Substantive  ....................................   25.0 

Mordant  .......................................  33  .  3 

Mercerized  wool  also  shows  an  increased  absorption  with 
respect  to  solutions  of  various  metallic  salts. 

The  exact  nature  of  the  action  of  caustic  soda  under  the 
conditions  given  is  rather  difficult  to  satisfactorily  explain. 
Through  a  microscopic  examination  of  the  treated  fibres  it 
appears  that  the  individual  scales  on  the  surface  of  the  wool 
are  more  or  less  fused  together  to  a  smooth  surface,  which  would 
account  for  the  great  increase  in  lustre.  The  additional  tensile 
strength  is  probably  accounted  for  by  the  same  fact,  the  closer 
adhesions  of  the  scales  giving  a  greater  rigidity  to  the  fibre. 
The  volatile  alkalies,  such  as  ammonia  and  ammonium  car- 
bonate, do  not  have  any  marked  deleterious  effect  on  wool, 
especially  at  low  temperatures;  hence  these  compounds  form 
excellent  scouring  materials.  The  hydroxides  of  the  alkaline 
earths,  though  less  violent  in  their  action  than  the  fixed  caustic 
alkalies,  nevertheless  decompose  wool.  Milk  of  lime,  even  in 
the  cold,  abstracts  most  of  the  sulphur,  and  also  causes  the 
fibre  to  become  hard  and  brittle  if  the  action  is  prolonged; 
the  wool  also  loses  its  felting  quality  to  a  considerable  extent. 
Barium  hydroxide,  as  previously  noted,  is  used  for  the  decom- 
position of  wool  in  the  preparation  of  lanuginic  acid. 

13.  Action  of  Oxidizing  Agents  on  Wool.  —  Toward  many 
other  chemical  reagents  wool  is  much  more  reactive  than 
cotton,  and  either  absorbs  from  solution  or  chemically  com- 


68  THE  TEXTILE  FIBRES 

bines  with  many  substances.  The  fibre  is  quite  readily  oxidized 
when  treated  with  strong  oxidizing  agents  such  as  potassium 
permanganate  or  bichromate,  becoming  greatly  deteriorated 
in  its  qualities. 

When  treated  with  solutions  of  hydrogen  peroxide  the  wool 
fibre  becomes  bleached,  as  the  coloring  matter,  or  pigment, 
is  destroyed.  Under  ordinary  conditions  of  use,  solutions  of 
hydrogen  peroxide  do  not  have  any  deleterious  effect  on  the 
qualities  of  the  wool  fibre  itself.  On  this  account  this  reagent 
is  largely  employed  for  the  bleaching  of  woolen  materials,  or 
materials  containing  mixed  cotton  and  woolen  yarns.  Instead 
of  employing  a  solution  of  hydrogen  peroxide  itself,  sodium 
peroxide  may  be  dissolved  in  acidulated  water  (with  sulphuric 
acid),  giving  a  slightly  acid  solution  of  hydrogen  peroxide. 
The  slight  excess  of  acid  is  used  for  the  purpose  of  completely 
neutralizing  all  of  the  caustic  soda  that  is  formed  when  sodium 
peroxide  reacts  with  water,  as  the  presence  of  any  free  caustic 
soda  in  the  bleaching  bath  would  be  injurious  to  the  wool. 
When  employed  for  active  bleaching,  the  bath  is  usually  made 
slightly  alkaline  by  the  addition  of  ammonia,  silicate  of  soda, 
borax,  or  sodium  phosphate. 

Dilute  solutions  of  potassium  permanganate  may  also  be 
employed  for  the  bleaching  of  wool.  The  solution  should  not 
contain  more  than  2-3  per  cent  of  potassium  permanganate 
on  the  weight  of  the  wool,  and  the  temperature  of  the  bath 
should  not  be  over  120°  F.,  otherwise  there  is  danger  of  damaging 
the  fibre.  When  steeped  in  such  a  solution  of  potassium  per- 
manganate the  wool  acquires  a  dark-brown  color  by  reason  of 
the  precipitation  of  a  hydrate  of  manganese  in  the  fibre.  Sub- 
sequent treatment  with  a  solution  of  oxalic  acid  or  of  sodium 
bisulphite  removes  the  manganese  compound,  leaving  the 
fibre  clear  and  white.  This  is  a  very  effective  method  of  bleach- 
ing wool,  as  a  good  white  can  be  obtained  in  a  short  space  of 
time;  the  fibre,  however,  always  acquires  a  harsh  feel  and  a 
scroop,  owing  to  the  oxidizing  action  of  the  permanganate  on 
the  outer  scales  of  the  fibre.  The  method  is  also  too  expensive 
for  general  use. 


WOOL  AND   HAIR  FIBRES  69 

14.  Action  of  Chlorin  on  Wool. — Toward  chlorin,  wool 
acts  in  a  peculiar  manner;  it  is  completely  decomposed  by 
moist  chlorin  gas,  but  in  weak  solutions  of  hypochlorites  it 
absorbs  a  considerable  amount  of  chlorin  and  is  strangely 
altered  in  its  properties.  It  becomes  harsh,*  has  a  high  lustre, 
and  acquires  a  silk-like  feel  or  "  scroop,"  at  the  same  time 
losing  its  felting  properties  though  its  attraction  for  coloring 
matters  in  general  is  largely  increased. 

Bromin  appears  to  have  a  similar  action  on  wool.  It  is 
claimed  to  have  the  advantages  over  chlorin  in  that  it  does 
not  turn  the  material  yellow,  and  that  in  mixtures  of  dyed 
and  undyed  wool  the  former  is  not  attacked.  This  latter 
statement  is  open  to  doubt. 

Chlorinated  wool  finds  quite  a  number  of  applications  in 
practice,  f  The  process  is  used,  for  instance,  for  the  purpose 
of  imparting  a  silk-like  gloss  to  the  fibre.  Again,  if  yarns  of 
chlorinated  wool  and  ordinary  wool  are  woven  together  in  pat- 
tern, and  the  fabric  afterward  fulled,  since  the  chlorinated 


*  According  to  a  recent  German  patent,  the  harshness  of  chlorinated  wool 
may  be  considerably  lessened  by  working  the  material  first  in  a  solution  of  a  salt 
such  as  citrate  of  zinc  or  acetate  of  iron,  or  of  sodium  stannate  or  aluminate;  this 
is  followed  by  a  second  bath  of  very  dilute  alkali,  after  which  the  goods  are 
exposed  to  the  air.  The  author,  however,  has  not  been  able  to  obtain  any 
satisfactory  results  on  testing  this  process. 

t  According  to  Pearson  (Jour.  Soc.  Dyers  &•  Col.,  1909,  p.  81)  the  following 
is  the  chlorination  method  in  use  for  the  manufacture  of  unshrinkable  woolen 
underwear.  The  fabric  is  treated  with  a  solution  of  sodium  hypochlorite  con- 
taining not  more  than  4.5  per  cent  of  available  chlorin.  After  each  addition 
of  the  hypochlorite  solution  the  liquid  is  acidified  with  hydrochloric  acid.  After 
the  chlorin  treatment  the  wool  is  thoroughly  rinsed,  and  then  treated  with  a 
bath  of  sodium  bisulphite  for  the  purpose  of  removing  excess  of  chlorin  from 
the  fibre  and  restoring  its  color.  A  final  washing  and  scouring  with  a  soap 
solution  containing  a  little  soda  ash  is  given.  Pearson  claims  that  chlorinated 
wool  may  be  distinguished  from  untreated  wool  by  allowing  a  drop  of  water  to 
fall  upon  it.  With  chlorinated  wool  the  drop  is  rapidly  absorbed,  forming  a  circular 
spot;  whereas  with  untreated  wool  the  drop  is  slowly  absorbed  and  the  outline 
of  the  wetted  portion  is  irregular.  Also  if  fabrics  of  the  treated  and  untreated 
wool  be  rubbed  together  a  considerable  electric  charge  will  be  formed.  This 
property  of  chlorinated  wool  had  formed  the  basis  of  a  patented  "electric"  belt. 
Garments  of  chlorinated  wool,  however,  do  not  wear  well,  and  are  rapidly  deterio- 
rated by  laundering. 


70  THE  TEXTILE  FIBRES 

wool  does  not  felt  it  will  not  shrink  up  like  the  remainder  of  the 
yarn,  and  in  consequence  the  pattern  will  be  brought  out  with 
very  good  effect;  a  great  variety  of  novelties  may  be  produced 
in  this  manner.  Finally,  the  property  of  chlorinated  wool 
to  dye  a  heavier  shade  than  ordinary  wool,  when  dyed  in 
the  same  bath,  is  also  utilized;  and  fabrics  with  beautiful 
two-color  effects  may  be  easily  obtained  in  this  manner  by 
weaving  the  chlorinated  wool  into  designs  with  ordinary  wool 
and  afterward  dyeing  with  suitable  coloring  matters. 

The  chlorination  of  the  woolen  yarn  is  carried  out  in  practice 
as  follows:  The  material  is  well  freed  from  all  greasy  matters 
by  a  preliminary  scouring;  this  must  be  very  thorough,  other- 
wise good  results  will  not  be  obtained,  as  the  yarn  is  liable 
to  finish  up  very  unevenly.  A  steeping  in  hydrochloric  acid 
next  takes  place;  the  solution  should  be  cold  and  have  a  density 
of  i^°  Tw.  The  wool  should  be  left  in  this  bath,  for  twenty 
minutes.  It  is  next  passed  into  a  solution  of  bleaching  powder 
standing  at  3°  Tw.  and  worked  for  ten  minutes,  after  which 
it  is  again  treated  with  the  solution  of  hydrochloric  acid  and 
washed  thoroughly.  It  is  said  that  sodium  hypochlorite  is 
better  to  use  than  chloride  of  lime,  and  sulphuric  acid  is  pref- 
erable to  hydrochloric,  showing  less  tendency  to  turn  the  mate- 
rial yellow.  The  yellow  color  due  to  the  chlorin  may  be  removed 
by  treatment  with  sulphurous  acid. 

15.  Action  of  Metallic  Salts;  Mordants. — With  neutral 
metallic  salts  wool  does  not  seem  very  reactive,  as  it  does 
not  absorb  them  appreciably  from  their  solutions.  With 
salts,  however,  which  are  acid  in  reaction  and  are  capable 
of  being  easily  dissociated,  such  as  alum,*  ferrous  sulphate, 
potassium  bichromate,  etc.,  the  wool  fibre  possesses  considerable 


*  According  to  Gelmo  and  Suida  (Monatsch.  /.  Chemie,  vol.  26,  p.  855)  when 
wool  is  boiled  for  one  hour  in  a  solution  of  alum  acidified  with  sulphuric  acid, 
a  considerable  hydrolysis  is  caused,  there  being  considerable  loss  in  weight, 
and  the  formation  of  soluble  amino  acids.  Some  of  the  decomposition  products 
resemble  peptones  in  their  action.  Wool  treated  with  a  o.i  per  cent  solution 
of  alcoholic  zinc  chloride  and  washed  shows  a  decidedly  decreased  affinity  for 
basic  dyes  and  a  greater  affinity  for  acid  dyes. 


WOOL  AND  HAIR  FIBRES  71 

attraction,  especially  when  boiled  in  their  solutions.*  On 
this  reaction,  in  fact,  are  based  the  important  methods  of 
mordanting  wool  with  various  metallic  salts  as  a  previous 
preparation  for  the  dyeing  of  many  coloring  matters. 

The  metallic  salt  chiefly  employed  for  the  mordanting  of 
wool  is  potassium  bichromate.  If  wool  is  simply  boiled  in  a 
dilute  solution  of  potassium  bichromate,  the  fibre  will  take  up 
from  solution  a  considerable  portion  of  the  chromium  compound, 
presumably  in  the  form  of  a  chromate  of  chromium;  that  is 
to  say,  a  combination  of  chromic  acid  with  chromic  oxide.  The 
substance  of  the  wool  fibre  itself  apparently  has  a  reducing 
action  on  the  potassium  bichromate.  It  has  been  found  that 
this  action  is  promoted  and  accelerated  by  the  presence  of  acids 
and  certain  organic  compounds  (such  as  tartar).  Therefore 
it  is  customary  to  add  such  compounds  to  the  mordanting  bath. 
Sulphuric  acid,  tartar,  lactic  and  formic  acids  are  chiefly  used 
for  this  purpose,  f 

*  Schellens  (Arch.  Pharm.,  1905,  p.  617)  has  furnished  some  interesting  experi- 
ments showing  the  relative  power  of  fixation  of  metallic  salts  possessed  by 
various  textile  fibrss.  With  solutions  of  ferric  chloride,  for  instance,  the  follow- 
ing results  were  obtained: 

Solution  No.  i  Solution  No.  2, 

Containing  Containing 

i  Per  Cent  of  Iron.        o.i  Per  Cent  of  Iron. 

Cotton-wool 0.112  0.112 

Filter-paper o .  23  o .  1 23 

Vegetable  silk i .  01  b .  56 

Jute o .  56  o .  44 

Raw  silk 0.67  0.67 

Wool o .  84  0.36 

The  figures  refer  to  the  weight  of  iron  fixed  by  i  gram  of  the  fibre  from  50  c.c. 
of  the  respective  solutions. 

f  When  wool  is  mordanted  with  potassium  bichromate  and  sulphuric  acid, 
compounds  of  chromic  acid  and  chromium  oxide  of  a  more  or  less  yellowish  color 
are  fixed  in  the  fibre.  By  increasing  the  proportion  of  sulphuric  acid  the  mordant 
has  a  greener  shade  and  is  richer  in  chromic  oxide.  According  to  Ulrich  (Zeit. 
physiol.  Chem.,  1908,  p.  25)  the  reduction  of  the  chromic  acid  is  brought  about 
by  the  products  formed  by  the  gradual  hydrolysis  of  the  fibre  substance  by  the 
acid.  When  lactic  and  formic  acids  are  employed  in  place  of  sulphuric  acid, 
they  simply  accelerate  the  reduction.  Experiments  on  the  action  of  formic 
acid  on  chromic  acid  have  shown  that  a  fairly  high  reaction  velocity  is  reached 
only  with  very  high  concentrations  of  the  formic  acid,  for  even  with  500  mole- 
cules of  formic  acid  per  molecule  of  chromic  acid,  the  reduction  is  not  complete 


72  THE  TEXTILE   FIBRES 

According  to  Siefert,*  when  wool  is  treated  with  a  solution 
of  ammonium  thiocyanate  and  then  steamed  a  considerable 
contraction  takes  place  without  injury  to  the  fibre;  consequently 
it  is  possible  to  produce  a  crepon  effect  in  this  manner  on  woolen 
cloth,  f  The  treated  wool  also  has  an  increased  affinity  for  acid 
dyes,  but  its  affinity  for  basic  dyes  is  reduced. 

16.  Action  of  Dyestuffs  on  Wool.— With  regard  to  coloring 
matters  wool  is  the  most  reactive  of  all  the  textile  fibres,  com- 
bining directly  with  acid,  basic,  and  most  substantive  dyestuffs, 
and  yielding,  as  a  rule,  shades  which  are  much  faster  than 
those  obtained  on  other  fibres. 

There  have  been  various  opinions  put  forward  as  to  the 
influence  in  dyeing  of  the  active  chemical  groups  in  wool.  If 
the  phenomena  of  dyeing  were  principally  of  a  chemical  nature 
we  would  expect  this  influence  to  be  a  considerable  one.  In 
the  case  of  acid  and  basic  dyes,  we  have  to  deal  with  bodies 
possessing  definite  chemical  characteristics;  that  is  to  say,  acid 
dyes  are  acid  in  nature,  while  basic  dyes  have  basic  properties. 
From  the  facts  previously  put  forward  that  wool  consists 
principally  of  an  amino  acid,  and  is  therefore  capable  of  exhibit- 
ing both  acid  and  basic  properties,  it  would  be  natural  to  expect 
that  in  dyeing  with  acid  coloring  matters  there  would  be  (to 
some  degree  at  least)  the  formation  of  a  compound  between  the 


after  boiling  for  one  hour.  Experiments  in  the  presence  of  wool  have  shown 
that  the  formic  acid  has  little  influence  on  the  reduction  process,  the  conversion 
of  the  chromic  acid  into  chromic  oxide  being  caused,  even  in  its  presence,  by 
the  products  formed  by  the  hydrolysis  of  the  fibre.  The  part  taken  by  the  formic 
acid  in  the  mordanting  of  wool,  therefore,  is  simply  to  accelerate  the  absorption 
of  the  chromium  compounds  by  the  fibre. 
*  Bull.  Soc.  Ind.  Mulhouse,  1899,  p.  86. 

f  Crepon  effects  on  woolen  cloth  made  by  the  printing  on  of  chemicals  which 
cause  a  shrinkage  of  the  fibre  may  be  produced  by  several  methods,  (i)  Schaef- 
fer's  process  consists  in  printing  on  a  suitable  resist,  then  treating  the  entire 
fabric  with  a  strong  solution  of  sodium  bisulphite  and  steaming.  This  causes 
a  shrinkage  of  the  entire  piece  except  at  the  portions  on  which  the  resist  is 
printed.  (2)  Siefert's  process  consists  in  the  use  of  calcium  or  barium  sulpho- 
cyanide  and  steaming.  Care  must  be  exercised  in  this  treatment,  however,  for 
the  wool  treated  with  sulphocyanide  is  very  tender  under  the  influence  of  steam. 
After  the  process  is  completed,  however,  the  wool  is  not  injured. 


WOOL  AND   HAIR  FIBRES  73 

acid  of  the  dyestuff  and  the  base  of  the  wool.*  Likewise, 
in  dyeing  with  basic  coloring  matters  the  basic  portion  of  the 
dyestuff  would  combine  with  the  acid  portion  of  the  wool. 
That  such  a  combination  in  reality  does  take  place  can  hardly  be 
doubted,  for  many  experimental  facts  have  been  adduced  lead- 
ing to  such  a  conclusion.  Aside  from  the  fact  that  wool  com- 
bines directly  with-  acid  and  basic  coloring  matters,  it  has  also 
been  shown  f  that  when  the  active  chemical  groups  in  the 
fibre  are  neutralized  by  proper  chemical  treatment,  the  reactivity 
of  wool  toward  acid  and  basic  dyes  respectively  is  much 
decreased.  The  acid  nature  of  wool  may  be  almost  completely 
neutralized  by  acetylation  with  acetyl  chloride,  and  the  result- 
ing fibre  shows  but  very  slight  reactivity  toward  basic  dyes, 
and  a  correspondingly  increased  reactivity  toward  acid  dyes.J 

*  In  the  dyeing  of  wool  with  acid  colors  it  is  generally  necessary  to  add 
sulphuric,  or  other  strong  acid,  to  the  dye-bath.  It  has  usually  been  the  accepted 
theory  that  these  dyes  are  sodium  salts  of  sulphonic  acids,  and  that  the  addition 
of  the  sulphuric  acid  causes  the  liberation  of  the  free  color-acid,  and  the  latter 
then  combines  with  the  basic  group  of  the  wool  fibre.  But  it  has  previously  been 
pointed  out  that  wool  combines  readily  with  sulphuric  acid,  and  that  wool  so 
treated  can  dye  with  the  acid  colors  without  further  addition  of  acid.  This  would 
seem  to  indicate  that  the  basic  group  of  wool  combines  with  sulphuric  acid,  and 
consequently  the  presence  of  the  latter  in  neutralizing  the  basicity  of  the  woo' 
should  decrease  its  affinity  for  acid  dyes,  according  to  the  above  view  of  the 
dyeing  process;  but  the  opposite  is  the  case.  Furthermore,  a  large  excess  of 
sulphuric  acid  above  the  amount  required  to  liberate  the  free  color-acid  of  the 
dyestuff,  should  prove  detrimental  to  the  dyeing.  Gelmo  and  Suida  (Monatsch. 
f.  Chemie,  vol.  26,  p.  855)  who  have  investigated  the  subject,  show  that  by  using 
purified  wool  and  dyeing  with  free  color-acids  the  intensity  of  the  resulting 
color  is  independent  of  the  presence  of  free  mineral  acid  in  the  dye-bath; 
hence  they  conclude  that  the  role  played  by  the  excess  of  acid  is  to  neutralize 
the  lime  combined  with  the  acid  groups  of  the  wool. 

f  Suida,  Farber-Zeit.,  1905. 

t  The  action  of  dyestuffs  on  the  fibres  has  also  been  explained  by  electrical 
effects.  Haldane,  Gee,  and  Harrison  (Proc.  Faraday  Soc.,  1910)  have  shown 
that  the  average  value  of  the  potential  difference  between  the  various  fibres  and 
water  is  as  follows: 

Cotton o .  06  volt 

Silk.  .' 0.22    " 

Wool 0.91    " 

This  seems  to  support  the  views  of  Pelet-Jolivet  and  Wild,  and  Knecht  and 
Battey,  that  dyestuffs  are  electrolytes,  and  ionization  is  increased  by  dilution 


74  THE  TEXTILE  FIBRES 

Suida  has  found  that  when  wool  is  heated  with  acetyl 
chloride  at  the  temperature  of  the  water-bath  a  copious  evolu- 
tion of  hydrochloric  acid  takes  place,  indicating  the  formation 
of  an  acetyl  compound.  Wool  which  has  been  thus  treated 
and  freed  from  all  excess  of  the  reagent  by  alternate  rinsing 
with  alcohol  and  water,  is  found  to  have  lost  to  a  great  extent 
its  affinity  for  the  basic  coloring  matters.  Wool  treated  with 
acetic  anhydride  shows  the  same  effect.  Microscopical  examina- 
tion in  both  cases  does  not  exhibit  any  structural  modifications 
in  the  fibre.  On  heating  wool  which  has  been  treated  in  this 
manner  with  a  weak  solution  of  ammonium  carbonate  (a  reagent 
which  is  capable  of  saponifying  acetyl  compounds),  the  wool 
again  regains  its  normal  character  with  respect  to  its  behavior 
toward  basic  dyestuffs.  A  change  of  the  same  character  in 
wool  is  produced  by  heating  the  fibre  on  the  water-bath  with 
alcohol  in  the  presence  of  a  small  amount  of  strong  sulphuric 
acid.  This  treatment  also  appears  to  form  an  ester  which  is 
saponified  by  treatment  afterward  with  an  alkali,  so  that  the 
wool  regains  its  original  condition. 

17.  Mildew  in  Wool. — If  wool  is  left  in  a  warm  place  in  a 
moist  condition  so  that  the  fibre  does  not  have  free  access  to 
plenty  of  fresh  air,  it  will,  soon  develop  in  spots  a  fungoid 
growth  or  mildew.  This  causes  the  fibre  to  become  tender  and 
eventually  rot.  This  fungoid  growth  will  develop  without 
any  sizing  ingredients  or  other  foreign  matter  being  present 
on  the  fibre.  It  rapidly  attacks  the  scales  on  the  surface  of  the 
fibre,  and  then  eats  into  the  inner  substance  of  the  wool.  ,  Under 
the  microscope  (see  Fig.  17)  this  fungoid  growth  appears  as 
two  forms:  (a)  Small  elliptical  cells  which  adhere  to  the  surface 
of  the  fibre  and  spread  out  from  it;  and  which  seem  to  colonize 
especially  at  the  joints  of  the  scales;  (b)  a  tree-like  growth 
consisting  of  several  cells  joined  together  and  branching  off 

and  rise  of  temperature.  Wool  and  silk  becoming  negatively  charged  when  in 
contact  with  water,  it  is  natural  that  basic  dyestuffs  (which  carry  a  positive 
charge)  should  be  capable  of  dyeing  them  from  neutral  solutions;  but  when  by 
the  addition  of  acid,  the  electrical  condition  of  the  fibre  is  changed,  the  affinity 
for  these  dyestuffs  is  diminished,  while  the  power  of  fixing  the  predominant  nega- 
tive ions  of  the  acid  dyes  is  increased. 


WOOL  AND   HAIR  FIBRES  75 

from  one  another;  these  grow  over  the  fibre  as  a  kind  of  filmy 
integument,  and  do  not  appear  to  corrode  the  wool  as  rapidly 
as  the  first  kind  of  cells.  Mildew  is  especially  apt  to  develop 
on  woolen  material  which  contains  a  small  amount  of  alkali, 
the  alkaline  reaction  probably  being  favorable  to  the  growth 
of  the  fungus.  Hence  the  tendency  of  wool  dyed  in  the  indigo- 
vat  to  develop  mildew  stains. 


FIG.  17. — Wool  Fibres  Attacked  by  Mildew.     (X3oo.) 

a,  fungus  growing  in  jointed  cells,  tree-like;  b,  fungus  growing  in  isolated  cells. 
(Micrograph  by  author.) 

18.  Microchemical   Reactions. — The   chemical   reactions   of 
the  wool  fibre  under  the  microscope  are  not  as  characteristic 
as    its    physical    structure.     With    concentrated    hydrochloric 
or  sulphuric  acid  the  fibre  gradually  dissolves  with  a  red  colora- 
tion;   with  nitric  acid  it  dissolves  with  much  difficulty  and 
with  a  yellow  color;   ammoniacal  copper  oxide  causes  the  fibre 
to  distend  considerably  with  gradual  disintegration,  bringing 
the  scale  markings  into  prominence;    solutions  of  copper  or 
ferric  sulphate  stain  the  fibre  black. 

19.  Hygroscopic    Quality. — Wool  is   more   hygroscopic  than 
any  other  fibre,  but  the  amount  of  moisture  it  will  contain  will 
vary  considerably  according  to  the  humidity  and  temperature 
of    the    surrounding   atmosphere.     Under   average    conditions, 
however,  it  will  contain  from  12  to  14  per  cent  of  absorbed  mois- 
ture.    The  hygroscopic  quality  of  wool  is  a  subject  of  consid- 
erable importance  in  the  commercial  handling  of  this  fibre,  for 


76  THE  TEXTILE  FIBRES 

the  weight  of  any  given  lot  of  wool  will  vary  within  large  limits 
in  accordance  with  climatic  conditions;  that  is  to  say,  the  ship- 
ment of  wool  from  one  locality  to  another  of  different  humidity 
and  temperature  will  cause  a  loss  or  gain  in  the  apparent  weight 
of  the  material.  So  important  a  factor  has  this  become  in  the 
commercial  relations  between  wool-dealers,  that  conditioning 
houses  for  wool  have  been  established  in  many  European  cen- 
tres for  the  purpose  of  carefully  ascertaining  the  actual  amount 
of  fibre  and  moisture  present  in  any  given  lot  of  wool,  the  true 
weight  being  based  on  a  certain  standard  percentage  of  mois- 
ture, or  so-called  "  regain."  This  percentage  varies  somewhat 
with  the  character  of  the  material  and  also  the  conditioning 
house,  ranging  from  16  to  19  per  cent.*  The  hygroscopic 
quality  of  wool  also  has  an  important  bearing  on  the  spinning 
and  finishing  processes  for  this  fibre,  it  being  necessary  to  main- 
tain a  definite  and  uniform  condition  of  moisture  in  order  that 
the  best  results  be  obtained  in  the  spinning  of  yarns  and  the 
finishing  of  the  woven  fabric. 

The  wool  fibre  also  appears  to  possess  a  certain  amount  of 
water  of  hydration,  which  is  no  doubt  chemically  combined  in 
some  manner  with  the  fibre  itself;  for  it  has  been  observed  that 
wool  heated  to  above  100°  C.  becomes  chemically  altered  through 
a  loss  of  water  at  that  temperature.  This  will  no  doubt  explain 
the  fact  that  air-dried  wool  is  superior  in  quality  to  that  dried 
by  means  of  artificial  heat,  which  usually  signifies  a  rather  ele- 


*  Wright  (Jour.  Soc.  Chem.  Ind.,  1909,  p.  1020)  as  the  result  of  an  investiga- 
tion of  the  absorption  of  moisture  by  wool  arrives  at  the  conclusion  that  the 
amount  of  moisture  which  a  wool  can  absorb  from  the  atmosphere  depends  on 
several  factors,  as  follows: 

(1)  The  relative  humidity  of  the  atmosphere. 

(2)  Pure  wool  fibre,  of  which  greasy  wool  contains  about  50  per  cent,  can  absorb 

from  1 8  to  20  per  cent  of  its  weight  of  moisture  from  the  atmosphere,  but 
this  amount  is  not  sufficient  to  account  for  all  the  moisture  absorbed 
by  the  dry  normal  wool  fibre. 

(3)  Natural  wool-fat,  present  in  greasy  wool  to  the  extent  of  about  17  per  cent, 

is  capable  of  absorbing  about  17  per  cent  of  its  weight  of  atmospheric 
moisture. 

(4)  Suint,  or  wool  perspiration,  is  present  in  greasy  wools  to  the  extent  of  about 

13  per  cent,  and  is  very  hygroscopic,  absorbing  60-67  Per  cent  of  moisture. 


WOOL  AND  HAIR  FIBRES 


77 


vated  temperature.  According  to  Persoz,  the  destructive 
action  of  high  temperatures  on  the  wool  fibre  may  be  prevented 
by  saturating  the  material  with  a  10  per  cent  solution  of  glycerol, 
after  which  treatment  the  wool  may  be  exposed  to  a  temperature 
of  140°  C.  without  being  affected.  The  explanation  of  this 
action  is  no  doubt  to  be  found  in  the  fact  that  glycerol  holds 
water  with  considerable  energy,  and  even  at  these  elevated 
temperatures  all  of  the  moisture  originally  present  in  the  wool 
is  not  driven  out  of  the  fibre.  In  order  to  economize  time,  it 
is  sometimes  necessary  to  dry  wool  rather  quickly  by  the  use 
of  suitable  machinery  and  high  temperatures.  Where  a  proper 
regulation  of  the  temperature  is  possible,  the  wet  wool  may 
be  subjected  to  quite  a  high  degree  of  heat  without  injury, 
for  the  fibre  itself  does  not  become  heated  up,  due  to  the  rapid 
evaporation  of  the  moisture.  As  the  fibre  becomes  drier, 
however,  it  is  important  that  the  temperature  fall,  so  that  at 
the  end  of  the  operation,  when  the  wool  has  become  dried  to 
its  normal  content  of  moisture,  the  temperature  should  be  that 
of  the  atmosphere. 

Too  much  importance  cannot  be  attached  to  the  proper 
drying  of  wool  in  all  of  its  stages  of  manufacture,  either  in 
scouring,  dyeing,  washing,  or  finishing.  If  wool  is  overdried; 
that  is,  if  the  moisture  in  it  is  reduced  to  an  amount  much  less 
than  that  which  it  would  normally  contain,  inferior  goods  will 
always  be  the  result,  for  the  intrinsic  good  qualities  of  the  fibre 
become  greatly  depreciated  every  time  such  a  mistake  is  com- 
mitted. 

The  following  table  shows  the  percentage  of  moisture  in 
air-dried  wool  and  when  exposed  to  an  atmosphere  saturated 
with  moisture,  as  compared  with  the  same  values  for  other 
fibres : 


Fibre. 

Air-dry. 

Saturated. 

Fibre. 

Air-dry. 

Saturated. 

Wool  
Silk  

8-14 
IO—  12 

30 
3O 

Manila  hemp.  .  .  . 
lute.  . 

8-12 
6 

40 
23 

Cotton 

6-8 

21 

Flax  

5-8 

12 

Ramie  

6-8 

18 

78  THE  TEXTILE  FIBRES 

The  influence  of  moisture  in  yarns  on  their  weaving  qualities  * 
is  an  interesting  factor.  Excess  of  moisture  over  the  normal 
amount,  appears  to  decrease  somewhat  the  tensile  strength  of 
worsted  yarns,  while  it  increases  considerably  the  elasticity. 
.With  cotton,  the  result  is  different;  the  elasticity  alters  but 
very  slightly  and  the  strength  increases  a  little.  Silk  appears 
to  follow  the  same  variations  as  wool. 

*  Barker,  Jour.  Soc.  Dyers'  &•  Col.,  1905,  p.  36. 


CHAPTER  IV 
SHODDY  AND  WOOL  SUBSTITUTES 

i.  Varieties  of  Shoddy. — Besides  the  natural  varieties  of 
wool  which  find  applications  in  the  textile  industries  we  have  a 
large  quantity  of  recovered  wool  employed  as  a  textile  fibre. 
This  is  obtained  by  tearing  up  woolen  rags  and  waste  (a  proc- 
ess known  as  "  garnetting,"  being  equivalent  to  a  coarse  card- 
ing), converting  it  back  into  the  loose  fibre  and  spinning  it  over 
again,  either  alone  or  in  admixture  with  varying  proportions 
of  pure  fibre  or  fleece  wool.  This  artificial  wool,  or  wool  sub- 
stitute, as  it  is  frequently  called,  is  also  obtained  from  rags  and 
waste  containing  wool  and  cotton,  or  even  silk;  the  vegetable 
fibre  being  destroyed  by  chemical  treatment,  thus  leaving  the 
animal  fibre  to  be  extracted  and  used  again.  On  this  account 
it  is  sometimes  known  as  extract  wool.  The  industry  of  con- 
verting recovered  fibre  into  yarns  and  fabrics  has  assumed  of 
late  enormous  proportions,  and  nearly  all  cheap  woolen  goods 
contain  a  high  percentage  of  these  wool  substitutes  in  their 
composition.  Depending  on  its  source  of  production,  this 
recovered  wool  will  vary  largely  in  its  quality,  and  according  to 
its  origin  and  nature  it  is  classed  under  several  names,  chief 
among  which  are  the  following: 

(a)  Shoddy.  Though  this  name  is  frequently  applied  to  all 
manner  of  recovered  fibre,  it  is  more  specifically  used  to  desig- 
nate that  which  is  derived  from  all-wool  rags  or  waste  which 
have  not  been  felted,  or  only  to  a  slight  degree,  also  from  knit 
goods,  shawls,  flannels,  and  similar  fabrics;  also  yarn  and  fabric 
waste  from  manufacturing  processes.  These  materials  are  known 
in  trade  as  "  softs."  They  yield  the  best  quality  of  fibre,  the 
average  length  of  which  is  about  one  inch,  while  the  variation 

79 


80  THE  TEXTILE   FIBRES 

in  length  is  from  1.4  to  0.2  inch.  In  many  cases  it  is  almost 
equal  in  quality  to  a  fair  grade  of  fleece  wool,  and  is  used  in  the 
production  of  many  high-grade  fabrics.  Shoddy  is  occasionally 
spun  up  alone  into  rather  coarse  counts  of  yarn;  but  it  is  more 
often  mixed  with  fleece  wool  and  manufactured  into  a  variety 
of  average  grade  yarns. 

(b)  Mungo  refers  to  the  fibre  obtained  from  woolen  material 
which  has  been   fulled   or  felted  considerably;    to  disintegrate 
the  rags  the  fibres  must   be  torn  apart,  and   consequently  it 
yields  fibres  of  shorter  staple  and  less  value  than  the  preced- 
ing.    The  length  of  fibres  in   mungo  varies  from  0.8   to   0.2 
inch;   and  on  this  account  is  never  worked  up  alone  into  yarn, 
but  is  mixed  with  new  wool  or  cotton  and  generally  spun  into 
low  counts  of  filling  yarn.    Since  mungo  consists  of  a  fibre  which 
has  already  been  heavily  felted,  it  is  easy  to  understand  that 
it  will  have  lost  much  of  its  capacity  for  further  felting. 

(c)  Extract  wool  is  that  obtained  from  mixed  wool  and  cotton 
rags  and  waste,  and  has  to  undergo  the  process  of  carboniza- 
tion, whereby  the  vegetable  fibre  is  destroyed.     This  process 
is  generally  carried  out  by  steeping  the  rags  in  a  solution  of 
sulphuric  acid  (6°  Tw.)  at  140°  to  180°  F.  and 'then  drying, 
whereupon  the  vegetable  fibres  are  decomposed  and  are  easily 
dusted  out  by  willowing,  the  wool  fibres  being  scarcely  affected. 
The  excess  of  acid  is  then  removed  by  treatment  with  soda- 
ash   and   washing.     The   fibres   obtained   are   sometimes   over 
one  inch  in  length.     Extract  wool  is  sometimes  called  alpaca, 
and  varies  much  in  its  length  of  staple  and  other  qualities. 

Besides  these  well-known  varieties  of  recovered  wool  there  are 
a  number  of  others  to  be  met  with  in  commerce,  such  as  Thibet 
wool,  which  is  usually  obtained  from  light-weight  cloth  clippings 
and  waste.  Cosmos  fibre  is  a  very  low-grade  material,  usually 
containing  no  wool  at  all,  being  made  by  converting  flax,  jute, 
and  hemp  fabrics  back  to  the  fibre.  Peat  fibre  is  a  product 
obtained  from  partially  decomposed  peat.  It  is  mixed  with 
wool  for  yarns  to  be  used  in  the  manufacture  of  horse-cloths, 
mats,  etc.  Wood-wool  is  a  somewhat  similar  product  obtained 
from  the  long  bleached  fibres  of  wood.  Even  the  short  down 


SHODDY  AND  WOOL  SUBSTITUTES  81 

obtained  in  the  shearing  of  woolen  cloths  is  used,  it  being 
employed  as  a  filler.  The  process  of  using  it  is  called  "  impreg- 
nating," and  consists  in  fulling  the  short  waste  into  the  cloth 
on  the  under  side. 

2.  Examination  of  Shoddy. — Woolen  fibres  consisting  of 
shoddy  sometimes  offer  a  characteristic  appearance  under  the 
microscope,  sufficient,  at  least,  to  distinguish  them  from  fibres 


FIG.  18. — Microscopic  Appearance  of  Shoddy,  showing  the  varied  Character  of 
the  Fibres.     (X35O.)     (Micrograph  by  author.) 

of  new  wool.  A  sample  of  shoddy  generally  shows  the  presence 
of  other  fibres  besides  wool,  and  fibres  of  silk,  linen,  and  cotton 
are  frequently  to  be  observed  (Fig.  18).  Also,  the  colors  of  the 
different  woolen  fibres  present  are  frequently  quite  varied,  so 
that  shoddy  usually  presents  a  multi-colored  appearance  under 
the  microscope.  A  very  striking  appearance,  also,  is  the 
simultaneous  occurrence  of  dyed  and  undyed  fibres;  the  diam- 
eters of  the  fibres  will  also  vary  between  large  limits,  the  variation 


82  THE  TEXTILE   FIBRES 

in  this  respect  being  much  more  than  with  fleece  wool.  Some 
samples  of  shoddy  will  also  show  a  large  number  of  torn  and 
broken  fibres,  and  usually  the  external  scales  are  rougher  and 
more  prominent. 

It  must  be  borne  in  mind,  however,  that  pure  wool  may 
also  show  the  presence  of  small  quantities  of  vegetable  fibres 
at  times.  These  often  arise  from  the  occurrence  of  burrs 
(bristly  and  barbed  seeds  of  various  plants)  in  the  original 
fleece.  South  American  wools  are  especially  liable  to  contain 
such  burrs;  in  many  cases  these  are  incompletely  removed, 
and  may  ultimately  appear  even  in  the  woven  cloth.  This 
frequently  explains  the  existence  of  short  fibres  or  vascular 
bundles  of  vegetable  matter  in  cloth.  Isolated  fibres  of  woody 
tissue  and  cotton  may  also  accidently  creep  in  through  a  variety 
of  causes.  According  to  Hohnel,  samples  of  pure  wool  may 
easily  contain  as  much  as  \  per  cent  of  vegetable  fibre.  The 
latter  authority  also  states  that  the  vegetable  fibres  of  shoddy, 
as  a  rule,  are  removed  by  carbonizing;  hence  the  absence  of 
cotton,  linen,  etc.,  must  not  be  taken  as  a  criterion  to  distinguish 
between  pure  wool  and-  shoddy.  When,  however,  cotton 
(always  dyed)  or  cosmos  fibre  occurs  in  at  least  a  quantity  of 
one  per  cent,  this  may  be  taken  as  a  direct  indication  of  the 
presence  of  shoddy,  as  it  would  scarcely  ever  happen  that  pure 
wool  is  adulterated  with  cotton;  this  only  happens  by  admixture 
with  shoddy  wool.  Undyed  cotton,  unless  present  in  consider- 
able amount,  cannot  be  considered  as  a  suspicious  component. 

The  determination  of  the  length  of  staple  is  also  a  rather 
unreliable  indication  as  to  the  presence  of  shoddy,  for  there 
are  varieties  of  shoddy  wools  which  are  longer  in  staple  than 
many  fleece  wools;  and  also  woven  goods,  though  composed 
entirely  of  fleece  wool,  may  show  the  presence  of  a  large  num- 
ber of  short  fibres  caused  by  the  shearing  of  the  surface  of  the 
cloth,  and  by  the  tearing  of  the  fibres  in  heavy  fulling. 

Where  woolen  cloth  has  been  impregnated  or  filled  with 
short  fibres  obtained  from  clippings,  such  may  usually  be  recog- 
nized by  teasing  the  sample  out  with  a  stiff-bristle  brush.  Good 
cloth  should  not  yield  over  \  per  cent  of  clipped  fibres  from  both 


SHODDY  AND  WOOL  SUBSTITUTES  83 

sides.  When  the  amount  of  such  fibres  is  at  all  considerable, 
they  may  be  used  as  serviceable  material  to  test  microscopically 
for  shoddy,  as  they  are  most  likely  to  be  made  up  of  this  char- 
acter of  wool. 

Fine  fleece  wools  hardly  ever  show  the  absence  of  epidermal 
scales  (though  this  is  frequently  the  case  with  coarse  wools); 
hence,  if  examples  of  such  fine  wools  are  found  showing  a  lack  of 
epidermis,  it  may  usually  be  taken  as  an  indication  of  shoddy. 

Hohnel,  however,  calls  attention  to  the  fact  that  the  fol- 
lowing conditions  previous  to  the  manufacturing  process  itself 
have  considerable  influence  on  the  good  structure  and  integrity 
of  the  wool  fibre:  Badly  cut  staple,  lack  of  attention  in  raising 
the  sheep,  poor  pasturage,  sickness  of  the  animal,  the  action 
of  urine,  snow,  rain,  dust,  etc.,  packing  the  wool  in  a  moist 
condition,  rapid  and  frequent  changes  of  moisture  and  tem- 
perature, the  use  of  too  hot  or  too  alkaline  baths  in  scouring, 
scouring  with  bad  detergents,  etc.  These  influences  may  lead 
to  the  partial  removal  of  the  epidermis,  and  to  the  softening 
and  breaking  of  the  ends  of  the  fibre.  There  must  also  be 
considered  the  influence  of  willowing,  carding,  combing, 
spinning,  weaving,  gigging,  fulling,  acidifying,  washing,  shearing, 
pressing,  etc.,  from  which  it  is  easy  to  understand  why  even 
fibres  of  fleece  wool  may  show  the  entire  absence  of  epidermis. 
Hohnel  also  criticises  other  alleged  characteristics  of  shoddy, 
such  as  torn  places  in  the  fibre,  unevenness  in  diameter,  etc., 
claiming  that  these  can  hardly  be  taken  as  an  indication  of  shoddy 
because  such  marks  are  often  regularly  present  in  many  fleece 
wools.  Most  samples  of  shoddy,  in  fact,  show  scarcely  any 
structural  differences  from  ordinary  fleece  wool.*  The  ends 

*  It  is  often  impossible  to  determine  by  chemical  or  physical  examination 
if  a  sample  of  woven  cloth  contains  shoddy  or  pure  fleece  wool  only.  There 
are  many  forms  of  shoqMy  (remanufactured  fibre)  which  are  composed  of  wool 
fibres  of  excellent  quality;  such,  for  instance,  as  the  shoddy  obtained  from  knit- 
goods  or  from  tailors'  clippings  of  loosely  woven  fabrics.  It  is  possible,  in  fact, 
to  have  a  fabric  composed  entirely  of  shoddy  to  exhibit  a  better  quality  of  fibre 
on  examination  than  a  fabric  which  may  be  composed  of  pure  (though  inferior) 
fleece  wool.  It  must  also  be  borne  in  mind  that  when  a  fabric  is  unravelled  and 
teased  apart  so  that  an  examination  of  the  fibres  may  be  made,  the  fibres  so 


84  THE  TEXTILE  FIBRES 

of  shoddy  fibres,  however,  usually  present  a  torn  appearance ; 
at  least  there  is  a  great  predominance  of  such  fibres  in  shoddy, 
whereas  in  fleece  wool  this  appearance  is  seldom  to  be  observed, 
the  end  of  the  fibre  being  cut  off  sharply.  The  appearance 
of  the  torn  fibres  may  be  easily  observed  under  the  microscope; 
the  epidermis  being  entirely  torn  away,  as  well  as  the  marrow 
which  is  sometimes  present,  while  the  fibrous  cortical  layer 
is  frayed  out  like  the  end  of  a  brush.  This  appearance  can 
usually  be  rendered  more  distinct  by  previously  soaking  the 
fibres  in  hydrochloric  acid.  Sheared  fibres  are  recognized  by 
being  very  short  and  by  having  both  ends  sharply  cut  off. 

The  color  of  the  fibres  is  also  a  characteristic  appearance  of 
shoddy,  as  the  rnajority  of  shoddy  is  made  up  of  variously 
colored  wools.  It  is  of  rare  occurrence  that  rag-shoddy  possesses 
a  single  uniform  color.  Hence  if  a  sample  of  yarn,  possessing 
a  single  average  color,  on  examination  reveals  the  presence  of 
variously  colored  fibres,  it  is  almost  a  positive  indication  of 
shoddy.  In  this  connection  it  must  not  be  forgotten,  however, 
that  differently  colored  wools  are  frequently  mixed  together 
previous  to  spinning,  to  make  so-called  "  mixes."  As  a  rule, 
however,  only  two  to  three  colors  are  used  together;  therefore 
a  purposely  mixed  yarn  of  this  description  is  not  likely  to  be 
confounded  with  a  shoddy  yarn  where  individual  fibres  of  a 
large  number  of  colors  are  nearly  always  shown. 

obtained  in  reality  constitute  a  form  of  shoddy,  having  been  previously  sub- 
jected to  the  various  operations  of  manufacture.  Whereas  it  is  quite  possible  to 
definitely  decide  whether  a  sample  of  loose  wool  (or  even  yarn)  contains  shoddy 
or  not,  in  very  many  cases  it  would  be  impossible  to  make  such  a  statement 
regarding  a  piece  of  woven  cloth  from  an  analysis  or  examination  of  the  latter. 
After  all,  the  question  as  to  the  use  of  shoddy  in  woolen  fabrics,  resolves  itself 
into  a  question  as  to  the  quality  of  the  fibre,  irrespective  of  the  fact  as  to  whether 
the  fibre  was  derived  first  hand  from  the  fleece  or  from  some  other  source  of 
manufactured  material. 


CHAPTER  V 

MINOR  HAIR   FIBRES 

1.  The    Minor   Hair    Fibres. — Besides    the    fibre    obtained 
from  the  domestic  sheep,  there  are  large  quantities  of  hair  fibres 
employed  in  the  textile  industries  and  obtained  from  related 
species  of  animals,  such  as  goats,  camels,  etc.     As  these  are 
all  more  or  less  utilized  in  conjunction  with  wool  itself,  and  are 
subjected  to  similar  operations  in  manufacturing,  it  will  not 
be  out  of  place  to  consider  them  at  this  point.     The  chief  among 
these   related  fibres   are   mohair,   cashmere,   alpaca,   cow-hair, 
and  camel-hair. 

2.  Mohair. — This  fibre  is  obtained  from  the  Angora  goat, 
an  animal  which  appears  to  be  indigenous  to  western  Asia, 
being  largely  cultivated  in  Turkey  and  neighboring  provinces. 
The  fleece  is  composed  of  very  long  fibres,  fine  in  staple,  and 
with  little  or  no  curl.     The  fibre  is  characterized  by  a  high 
silky  lustre.     Mohair  is  now  grown  to  a  considerable  extent 
in    the   Western    States,    principally   Oregon,    California,    and 
Texas,  the  goats  having  originally  been  imported  from  Turkey; 
there  is  also  a  large  quantity  of  mohair  grown  in  Cape  Colony. 
The  principal  mohair  clips  (1902)  are  as  follows: 

Turkey 8,500,000  Ibs. 

Cape  Colony 7,500,000   '  * 

United  States 1,250,000  " 

The  principal  use  of  mohair  is  for  the  manufacture  of  plushes, 
braids,  fancy  dress  fabrics,  felt  hats,  and  linings.  The  charac- 
ter of  fabric  in  which  it  may  be  employed  is  rather  limited  on 
account  of  the  harsh  wiry  nature  of  the  mohair  fibre,  and  the 
fact  that  it  will  not  felt  to  any  degree.  Domestic  mohair 
(American)  has  only  about  two-thirds  of  the  value  of  the  foreign 

85 


86  THE  TEXTILE  FIBRES 

fibre;  mohair  in  general  has  quite  a  large  amount  of  kempy 
fibre  (which  will  not  dye),  but  the  domestic  variety  contains 
about  15  per  cent  more  kemp  than  the  foreign,  hence  the  lower 
value  of  the  former.  Another  reason  for  this  lessened  value 
is  that  foreign  mohair  always  represents  a  full  year's  growth 
(the  fibres  being  9  to  12  inches  in  length),  whereas  a  great  deal 
of  domestic  mohair  is  shorn  twice  a  year.  This  is  especially 
true  of  that  grown  in  Texas;  the  hair  commences  to  fall  off  the 
goats  in  that  district  if  allowed  to  grow  for  the  full  year.  In 
judging  of  the  quality  of  mohair,  the  length  and  lustre  are  of 
more  value  than  the  fineness  of  staple.  The  finest  grades  of 
domestic  mohair  come  from  Texas,  the  fibre  from  Oregon  and 
California  being  larger  and  coarser.  In  Oregon  the  fleece  is 
grown  for  a  full  year,  and  consequently  the  fibre  is  very  long. 
The  average  weight  of  the  fleece  from  Oregon  goats  is  4  pounds 
while  in  Texas  it  is  only  2\  pounds.  Foreign  mohair  varies 
much  in  quality,  depending  upon  the  district  in  which  it  is 
grown;  as  a  rule,  the  finer  varieties  are  shorter  in  staple,  the 
finest  being  about  9  inches  in  length.  Foreign  mohair  can  be 
spun  to  as  high  a  count  as  6o's,  whereas  the  finest  quality  of 
domestic  mohair  can  only  be  spun  to  as  high  as  40*5.  The 
coarsest  varieties  of  mohair  are  used  in  carpets,  low-grade  woolen 
fabrics,  and  blankets. 

The  term  mohair,  in  a  general  sense,  is  becoming  an  extensive 
one,  including  the  fibre  from  the  fleeces  of  goats  of  various 
crosses  with  the  true  Angora. 

Microscopically,  the  mohair  fibre  is  possessed  of  the  follow- 
ing characteristics:  The  average  length  is  about  18  cm.,  and  the 
diameter  about  40  to  50  ^  and  very  uniform  throughout  the 
entire  length  (see  Fig.  19).  The  epidermal  scales  can  only 
be  observed  with  difficulty,  as  they  are  very  thin  and  flat, 
though  regular  in  outline.  They  are  also  very  broad,  a  single 
scale  frequently  surrounding  the  entire  fibre;  the  edge  of  the 
scale  is  usually  finely  serrated.  The  best  grades  of  fibres  show 
no  medulla,  but  there  are  usually  to  be  found  (especially  in 
domestic  mohair)  coarse,  thick  fibres  possessing  a  broad  medul- 
lary cylinder,  thus  resembling  the  structure  of  ordinary  goat- 


MINOR  HAIR  FIBRES  87 

hair,  from  which,  however,  they  are  to  be  distinguished  by 
being  more  slender  and  more  uniform  in  their  diameter.  Longitu- 
dinally, the  fibre  exhibits  coarse,  fibrous  striations,  approximat- 
ing the  appearance  of  broad  and  regularly  occurring  fissures.* 
Due  to  the  fact  that  the  surface  scales  lie  very  flat  and  do  not 
project  over  one  another,  the  edge  of  the  fibre  is  very  smooth, 
showing  scarcely  any  serrations  at  all,  which  accounts  for  its 
utter  lack  of  felting  qualities.  The  outer  end  of  the  fibre  is 


FIG.  19. — Mohair  Fibres.     (X35o.)     (Micrograph  by  author.) 

either  slightly  swollen  or  blunt,  but  never  pointed.  When 
viewed  under  polarized  light  the  fibres  occasionally  show  the 
presence  of  a  medullary  canal,  which  appears  as  a  hollow  space, 
giving  an  illumination  somewhat  resembling  that  of  a  bast 
fibre,  and  covering  from  one-fourth  to  one-half  of  the  diameter. 
Mohair  noils  are  the  short  fibres  separated  in  the  combing 
of  mohair. 

*  These  striations  are  usually  much  more  pronounced  than  those  to  be  found 
in  sheen's  wool. 


88 


THE  TEXTILE  FIBRES 


3.  Cashmere  is  remarkable  for  its  softness,  and  is  much  used 
in  the  woolen  industry  for  the  production  of  fabrics  requiring 
a  soft  nap.  Cashmere  is  the  fibre  employed  in  the  manufacture 
of  the  famous  Indian  shawls.  There  are  two  qualities  of  cash- 
mere wool,  the  one  consisting  of  the  fine,  soft  down-hairs  and 
the  other  of  long,  coarser  beard-hairs.  The  former  are  from 
i  i  to  3^  inches  in  length,  13  p.  in  diameter,  while  the  latter  are 
from  3  ^  to  4^  inches  in  length  by  60  to  90  [L  in  diameter.  The 
wool-hairs  show  visible  scales  but  no  definite  medulla,  whereas 


FIG.  20. — Wool-hairs  of  Cashmere.     (X3SQ.)     (Micrograph  by  author.) 

the  beard-hairs  possess  a  well-developed  medulla.  The  cortical 
layer  is  coarsely  striated  and  shows  characteristic  fissures. 
At  the  point  of  the  fibre  the  epidermal  scales  are  either  entirely 
absent  or  are  so  thin  as  to  be  scarcely  visible.  The  fibre  is 
very  cylindrical;  the  scales  have  their  free  edge  finely  serrated, 
and  the  edge  of  the  fibre  also  presents  the  same  appearance. 
(See  Fig.  20.) 

4.  Goat-hair. — Besides  mohair  and    cashmere,    the  hair  of 
the  common  goat  is  also  used  at  times.     It  has  the  following 


MINOR  HAIR  FIBRES 


89 


microscopical  characteristics  (Hohnel):  It  is  white,  yellow, 
brown,  or  black  in  color,  and  generally  from  4  to  10  cm.  long. 
It  consists  largely  of  beard-hairs,  which,  like  pulled  wool, 
nearly  always  show  the  hair-root.  The  average  hair  exhibits  the 
following  structure  (see  Fig.  21):  At  the  base  it  is  about  80  to 
90  [ji  thick;  the  root  is  about  ^  mm.  long;  the  marrow  is  just 
visible  at  the  root,  then  rapidly  increases  in  thickness,  so  that 
a  few  millimeters  from  the  base  it  is  50  y.  thick,  where  the 


FIG.  21. — Hair  of  Common  Goat.     (X350.)     Showing  hair-root  and   medullated 
fibre.     (Micrograph  by  author.) 


thickness  of  the  hair  amounts  to  from  80  to  90  [i.  The  cortical 
layer  from  this  point  on  forms  a  very  thin  cylinder.  The  cross- 
section  is  round;  the  epidermis  consists  of  broad  scales  about 
15  [ji  long,  the  forward  edges  of  which  are  scarcely  thickened, 
but  appear  as  if  terminating  in  a  sharp  line;  furthermore  they 
are  not  serrated.  The  medullary  cells  are  thick-walled,  narrow, 
and  flattened.  Toward  the  end  the  hair  is  very  brittle  and 
easily  broken.  Other  authors  note  the  presence  of  very  narrow 


90 


THE  TEXTILE    FIBRES 


air-clefts  between  the  medullary  cells  as  being  quite  character- 
istic of  goat-hair.  Colored  goat-hair  shows  the  presence  of  pig- 
ment-matter in  all  of  its  tissues;  in  such  fibres  the  marrow 
appears  black. 

Hanausek  *  calls  attention  to  the  fact  that  certain  kinds  of 
sheep's  wool  closely  resemble  goat's  wool  having  numerous 
beard-hairs  present  showing  a  broad  medulla.  Under  the 
microscope  goat-hairs  in  their  middle  part  are  characterized 
by  broad,  short,  parallel  medullary  cells.  Air  (together  with 
dried  granular  contents)  is  generally  present  in  the  medullary 
cells  of  white  hairs,  giving  the  medulla  the  appearance  of  a 


FIG.  22. 

A,  sheep's    wool;   B,  goat's    wool;    W,  wool-hair;    G,  beard-hair;    e,  epidermis; 
/,  fibre  layer;   m,  medulla.     (After  Hanausek.) 

broad,  black  band.  In  the  beard-hairs  of  coarse  sheep's 
wool  the  appearance  is  much  the  same  (Fig.  22,  A  and  B).  If, 
however,  the  fibres  are  mounted  in  potash  and  gently  warmed, 
they  swell  greatly  and  the  medullary  cells  stand  out  sharply 
and  distinctly.  In  wool  these  appear  as  large  round  cells,  while 
in  goat's  hair  they  remain  elongated  and  the  original  parallel 
arrangement  is  not  altered  (see  Figs.  23.  A  and  B}.  According 
to  Hanausek  this  difference  is  sufficiently  characteristic  to  per- 
mit of  the  distinction  between  sheep's  wool  and  goat's  wool  at 
a  glance. 

*  Microscopy  of  Technical  Products,  p.  134. 


MINOR  HAIR  FIBRES 


91 


5.  Alpaca  and  its  varieties  vicuna  and  llama,  have  the  dis- 
advantage of  being  mostly  colored  from  brown  to  black. 
Though  largely  used  in  South  America  for  the  production  of 
various  fabrics,  they  do  not  find  much  application  in  the 
general  textile  industry.  There  is  another  product  in  trade 
which  goes  by  the  name  of  vicuna  (French  vicogne)  which  must 
not  be  confused  with  the  true  South  American  fibre,  it  being 
simply  a  trade  name  for  a  mixture  of  cotton  and  wool.*  The 
name  alpaca  is  also  given  to  a  variety  of  wool  substitute.  The 
South  American  wools  often  give  rise  to  wool-sorter's  disease 


FIG.  23. 

A,  beard-hair  of  sheep,  and  B,  of  goat  after  warming  in  potash;  /,  fibre  cells, 
becoming  disintegrated;  m,  medullary  cells,  swollen  and  no  longer  showing 
granular  contents.  (After  Hanausek.) 

to  those  handling  them.  This  disease  is  anthrax  and  is  caused 
by  the  presence  of  a  certain  microbe  in  the  fibre,  f  Wool- 
sorter's  disease  is  caused  by  bacillus  anthracis,  which  may  enter 
the  system  either  by  the  skin  (through  the  medium  of  an  abrasion 
or  cut)  or  by  the  internal  organs,  being  introduced  with  the  food. 

1  "Gorilla"  yarn  is  a  complex  mixture  of  such  hair  fibres  as  alpaca,  sheep's 
wool,  and  mohair,  with  cotton  and  silk  waste.  It  is  rugged  and  knotty  in 
appearance,  and  is  chiefly  used  for  the  manufacture  of  ladies'  dress  material. 

f  All  alpaca,  cashmere,  Persian  and  camel-hair  fleeces  should  be  opened  over 
a  fan  with  a  down  draught.  Van  mohair  or  Turkish  mohair  should  be  washed 
and  sorted  while  damp.  Persian  wool  should  be  disinfected  before  sorting  (The 
Text.  Mfr.,  1908,  p.  225). 


92  THE  TEXTILE  FIBRES 

In  the  former  case  it  gives  rise  to  pustules,  which  become  painful 
and  cause  excessive  perspiration,  fever,  delirium,  and  sundry 
disorders.  In  the  latter  case  it  gives  rise  to  the  most  serious 
results,  leading  to  blood-poisoning  and  inflammation  of  the 
lungs,  which  often  prove  speedily  fatal. 

True  alpaca  is  obtained  from  the  cultivated  South  American 
goat  Auchenia  paco.  It  occurs  in  all  varieties  of  colors,  from 
white,  through  brown,  to  black.  The  reddish  brown  and  not 


FIG.  24. — Alpaca  Fibres.     (X3So.)     (Micrograph  by  author.) 

the  white  variety,  however,  is  the.  most  valuable.  Like  other 
goat-hairs,  alpaca  consists  of  two  varieties  of  fibres,  a  soft 
wool-hair  and  a  stiff  beard-hair.  The  wool-hairs  of  the  reddish 
brown  variety  are  from  10  to  20  cm.  in  length  and  from  n  to 
35  (i  in  diameter  (see  Fig.  24).  The  fibre  is  very  smooth,  the 
serrations  on  the  edge  being  faint  and  indistinct,  and  the 
scales  are  almost  imperceptible  and,  in  many  cases,  apparently 
absent  altogether;  the  diameter  is  also  very  uniform,  and  there 
are  coarse  brown  longitudinal  striations  but  no  medulla,  though 


MINOR  HAIR  FIBRES 


93 


isolated  medullary  cells  are  at  times  observed.  The  wool- 
hairs  of  the  white  variety  are  very  distinctly  serrated  on  the 
edge,  and  the  fibre  is  not  so  uniformly  thick.  The  beard- 
hairs  of  the  brown  variety  are  comparatively  few  in  number, 
are  from  5  to  6  mm.  in  length  and  about  60  (L  in  diameter,  and 
the  latter  is  very  uniform.  A  very  broad  continuous  medullary 
cylinder  is  present,  45  to  50  [L  wide;  the  medullary  cells  are 


v. 


FIG.  25.— Fibres  of  Alpaca.     (Hohnel.)     (X350.) 

a,  beard-hair  containing  medulla;  6,  wool-hair  free  from  medulla;  e,  cusp-like 
scales,  thin  and  broad;  k,  granulated  streaks  on  the  fibrous  layer;  m,  medul- 
lary cylinders;  z,  small  medullary  cells. 

very  indistinct,  but  are  filled  with  coarse  granules  of  matter. 
The  cortical  layer  shows  occasional  fissures,  and  the  brown 
coloring  matter  is  principally  distributed  through  the  external 
cortical  layer,  though  very  irregularly.  The  beard-hairs  of 
the  white  variety  also  occur  rather  sparingly;  they  are  from 
20  to  30  cm.  in  length,  and  35  y.  in  thickness  at  the  lower  end 
and  about  55  [L  towards  the  upper  end.  The  medulla  is  broad 


94  THE  TEXTILE  FIBRES 

and  continuous,  and  nearly  always  filled  with  a  coarsely  granu- 
lated matter  of  a  gray  color  (Fig.  25).  The  medulla  consists 
of  a  single  row  of  short  cylindrical  cells,  but,  as  the  walls  are 
very  thin,  the  cells  are  to  be  seen  only  with  difficulty.  The 
cortical  layer  is  coarsely  striated  and  frequently  shows  fibrous 
fissures;  the  edge  of  the  fibre  is  not  sharply  serrated. 

The  fibres  of  alpaca  are  coarser  than  either  vicuna  or  camel- 
hair,  and  the  thick  medullated  fibres  are  present  in  much  greater 
proportion  than  the  fine  wooly  fibres.  The  distribution  of  the 
pigment  matter  is  more  uniform  in  alpaca  fibres  than  in  those 
of  vicuna  or  camel-hair. 

6.  Vicuna  Wool  is  another  South  American  product  obtained 
from  Auchenia  viccunia,  the  smallest  of  this  general  class  of 
goat-like  camels.  It  is  not  a  cultivated  animal,  and  is  evidently 
disappearing,  hence  the  fibre  is  not  met  with  in  trade  to  any 
great  extent  at  the  present  time.  It  is  a  soft,  delicate  fibre, 
usually  of  a  reddish  brown  color,  and  much  resembles  alpaca, 
though  it  is  usually  finer  than  either  alpaca  or  camel-hair,  and 
is  characterized  by  a  very  soft,  almost  greasy,  touch.'  It  also 
shows  the  presence  of  a  fine  wool-hair  and  a  coarse  beard-hair; 
the  former  is  from  10  to  20  (i  in  diameter,  while  the  latter  is 
75  y.  wide.  The  scales  of  the  wool-hair  are  very  regular  and  rather 
easy  to  distinguish,  but  generally  no  medulla  is  to  be  seen.* 
The  cortical  layer  is  finely  striated  and  frequently  contains 
fibrous  fissures  (Fig.  26).  The  beard-hairs,  however,  show  a 
well-developed  medulla,  mostly  dark  in  color.  The  fibres  of 
the  wool-hair  are  very  uniform  in  diameter  and  about  20  cm. 
in  length. 

An  artificial  wool  substitute  also  goes  by  the  name  of 
vicuna  or  vicogne  yarn,  but  bears  no  resemblance  to  the  true 
South  American  fibre.  It  consists  principally  of  a  mixture 
of  cotton  with  sheep's  wool,  but  is  frequently  mixed  more  or 

*  Mitchell  and  Prideaux  (Fibres  Used  in  Textile  Industries,  p.  34)  call  attention 
to  the  fact  that  the  disposal  of  the  pigment  is  an  important  characteristic  of  the 
vicuna  fibre.  In  the  small  fibres  it  is  regularly  distributed  in  uniform,  faintly 
defined  dashes.  In  the  large  medullated  fibres,  however,  the  distribution  of  the 
pigment  may  take  a  different  form;  in  addition  to  the  streaks  and  lines  found  in 
the  smaller  fibres,  there  may  occasionally  be  noted  circular  patches  of  pigment. 


MINOR  HAIR   FIBRES 


95 


less  with  wools  and  coarse  beard-hairs  of  poor  spinning  qualities 
obtained  from  various  goats  (of  Asia  Minor),  from  camels,  and 
from  South  American  wools.  It  is  of  poor  quality  and  generally 
yellowish  brown  in  color.  It  is  only  used  for  felted  materials 
or  for  very  coarse  fabrics. 


FIG.  26.— Vicuna  Fibres.     (X3SO.)     (Micrograph  by  author.) 


7.  Llama  Fibre. — This  exhibits  scarcely  any  visible  surface 
scales,  but  has  well-developed  isolated  medullary  cells.  It  also 
consists  of  two  classes  of  fibres,  both  of  which  show  longitudinal 
striations  (Fig.  27).  The  wool-hair  is  from  20  to  35  y.  in 
diameter,  while  the  beard-hair  averages  150  rji.  The  llama  wool 
comes  from  the  Auchenia  llama,  a  cultivated  animal.  The 
wool  from  another  variety,  Auchenia  huanaco,  is  used  to  some 
extent  in  South  America,  though  it  seldom  appears  as  such 
in  general  trade.  This  latter  animal  is  not  cultivated,  but  is 
hunted  wild,  and  is  gradually  disappearing.  Huanaco  and 
llama  are  nearly  always  mixed  more  or  less  with  alpaca  and 
brought  into  trade  under  the  latter  name.  There  is  but  little 


96  THE  TEXTILE  FIBRES 

difference  to  be  found  among  these  three  fibres,  owing  to  the 
close  relationship  of  the  animals  from  which  they  are  derived, 
and  more  especially  as  different  portions  of  the  fleece  from  all 
varieties  of  Auchenia  give  wools  of  entirely  different  quality, 
with  respect  to  color,  fineness  of  staple,  and  purity  from  coarse 
stiff  hairs;  and  the  corresponding  portions  from  the  different 
animals  are  usually  graded  together. 


FIG.  27. — Llama  Fibres.     (X35o.)     (Micrograph  by  author.) 

8.  Camel-hair  is  used  to  quite  an  extent  in  clothing  material, 
and  is  characterized  by  great  strength  and  softness.  It  has 
considerable  color  in  the  natural  state,  which  does  not  appear 
capable  of  being  destroyed  by  bleaching;  hence  camel-hair 
is  either  used  in  its  natural  condition  or  is  dyed  in  dark  colors. 
There  are  two  distinct  growths  of  fibre  on  the  camel:  the  wool- 
hair,  which  is  a  fine  soft  fibre,  largely  employed  for  making 
Jager  cloth,  and  the  beard-hair,  which  is  much  coarser  and 
stiffer,  and  is  mostly  used  for  carpets,  blankets,  etc.  Both 


MINOR  HAIR  FIBRES 


97 


fibres  show  faint  markings  of  scales  on  the  surface  and  well- 
developed  longitudinal  striations.  The  beard-hair  always 
exhibits  the  presence  of  a  well-defined  medulla,  which  is  large 
and  continuous,  while  the  wool-hair  either  shows  only  isolated 
medullary  cells  or  none  at  all.*  The  diameter  of  the  wool-hair 
is  from  14  to  28  51,  while  the  beard-hair  averages  75  p  (see  Fig. 
28).  The  wool-hairs  are  about  5  to  6  cm.  in  length,  are  rather 
regularly  waved,  and  are  usually  yellow  to  brown  in  color; 


FIG.  28. — Camel-hair.     (X35O.)     (Micrograph  by  author.) 

« 

while  the  others  are  about  10  cm.  long  and  are  dark  brown  to 
black  in  color.  The  epidermal  scales  of  the  latter  are  quite 
rough,  which  give  the  edge  of  the  fibre  a  saw-toothed  appear- 
ance. The  presence  of  large  spots,  or  motes,  of  brown  color- 

*  According  to  Mitchell  and  Prideaux  (loc.  ciL,  p.  35)  the  fibres  of  camel-hair 
are  generally  coarser  than  those  of  vicuna,  a  greater  proportion  of  the  larger 
medullated  fibres  being  present.  The  scales  of  the  finer  fibres  are  also  less  con- 
spicuous than  those  of  vicuna,  hence  the  latter  has  a  softer  touch.  The  dis- 
tribution of  the  pigment  cells  in  camel-hair  is  very  irregular;  some  of  the  finest 
fibres  appear  to  have  none,  while  in  others  flecks  and  dashes  of  pigment  may  be 
seen  in  the  otherwise  clear  transparent  hair. 


98 


THE  TEXTILE   FIBRES 


ing  matter,  especially  in  the  medulla,  is  quite  characteristic.* 
These  are  usually  granular  in  form.  The  beard-hairs  of  the 
camel  are  to  be  distinguished  from  corresponding  cow-hairs 
by  smaller  diameter,  thicker  epidermis,  and  narrower  medullary 
cells  with  thicker  walls,  which  are  generally  darker  in  color 
than  the  enclosed  pigment  matter.  Camel-hair  is  to  be  dis- 
tinguished from  cow-hair  by  the  thick-walled  medullary  cells 
and  the  streaks  of  coloring  matter. 

Camel-hair  noils  are  the  short  fibres  obtained  from  the 
combing  of  camel-hair.  It  also  consists  of  two  kinds  of  fibre: 
(a),  very  fine,  curly,  reddish  or  yellowish  brown  hairs,  about 
4  inches  in  length,  and  known  in  trade  as  camel- wool;  and  (6), 
coarse,  straight,  dark  to  blackish  brown  body  hairs,  about 
2  to  2\  inches  in  length, 

*  Prideaux  (Jour.  Soc.  Chem.  Ind.,  1900,  p.  8)  gives  the  following  summary 
of  differences  between  vicuna,  camel-hair,  and  alpaca: 


Vicuna. 

Camel-hair. 

Alpaca. 

The    finest    fibres    of    the 

Intermediate  in  fineness; 

The  coarsest   fibres,  few 

three;  few  coarse  medul- 

medullated   fibres   com- 

non-medullated 

lated    examples;     scales 

mon;    scales  most  con- 

least conspicuous 

spicuous 

Largest  difference  in  size 

— 

Least  difference  between 

between  non-  and  medul- 

non-     and     medullated 

lated  fibres 

fibres 

Pigment    always    present, 

Many  of  the  smaller  fibres 

Many    fibres,    especially 

except  in  a  few  of  the 

colorless 

the  larger  ones,   color- 

large  opaque  medullated 

less. 

fibres 

Amount  of  pigment  very 

Amount  of  pigment  varia- 

Amount of  pigment  very 

uniform;  disposal  rather 

ble;    disposal  highly  ir- 

variable;   disposal  very 

regular;    circular  nuclei 

regular,    circular    nuclei 

regularly     diffused,     in 

rare,  and  only  in  medul- 

frequently seen  in  fibres 

pale    specimens    almost 

lated  fibres 

of  all  sizes.     Distinctive 

as  if  dyed;   circular  nu- 

streaks  and   blurs   well 

clei  never  seen 

marked 

Notwithstanding  these  characteristic  differences,  it  is  a  very  difficult  matter 
to  differentiate  definitely  between  these  three  forms  of  hair  fibres,  and  an  opinion 
as  to  which  fibre  is  under  consideration  must  usually  be  referred  to  other  con- 
siderations than  a  microscopic  test. 


MINOR  HAIR  FIBRES 


99 


9.  Cow-hair  is  extensively  employed  as  a  low-grade  fibre 
for  the  manufacture  of  coarse  carpet  yarns,  blankets,  and  a 
variety  of  cheap  felted  goods.  It  is  seldom  used  alone,  however, 
on  account  of  its  short  staple.  It  comes  principally  from 
Siberia.  The  diameter  of  cow-hair  varies  from  84  to  179  (JL 
and  the  length  from  ij  to  5  cm.  The  fibres  occur  in  a  variety 
of  colors,  including  white,  red,  brown,  and  black.  In  its  micro- 
scopic appearance  the  surface  of  the  fibre  is  rather  lustreless; 


m 


FIG.  29. — a,  Cow-hair;  b,  Goat-hair.     (Hohnel.) 
q,   characteristic   fissures  in   marrow;    m,   marrow  or  medulla   filled   with  air; 
/,  fibrous  fissures;     e,  tile-shaped  scales. 

the  ends  are  very  irregular,  being  blunt  and  divided.  The 
medullary  canal  is  well  marked,  occupying  about  one-half  the 
diameter  at  the  base  and  tapering  towards  the  free  end,  where 
it  occupies  only  one-fourth  the  diameter.  Isolated  medullary 
cells  are  also  of  frequent  occurrence  (Fig.  29).  Cow-hair  (includ- 
ing also  calf-hair)  nearly  always  shows  the  hair-root,  as  the 
fibres  are  removed  from  the  hide  by  liming  and  pulling. 


100  THE  TEXTILE  FIBRES 

Cow-hair  shows  the  presence  of  three  kinds  of  fibres: 

1.  Thick,  stiff  beard-hairs  from  5  to  10  cm.  in  length,  and 
retaining  a  long  narrow  hair  follicle;   above  this  is  the  neck  of 
the  hair,  containing  a  medullary  cylinder  consisting  of  a  single 
series  of  cells  as  well  as  isolated  medullary  cells.     At  this  part  of 
the  fibre  the  epidermal  scales  are  very  thin  and  broad,  and  the 
forward  edges  present  a  serrated  appearance;    the  neck  of  the 
hair  is  about  120  pi  in  thickness.     Above  this  the  hair  rapidly 
increases  to  about  130  (JL  in  thickness,  and  the  medullary  cylinder 
becomes   broad    (75   y.)    and    consists    of  narrow  brick-shaped 
elements,  arranged  one  on  top  of  the  other.     The  cortical  layer  is 
finely  striated,  the  epidermis  is  indistinct,  and  the  edge  of  the 
fibre  is  smooth.     The  medullary  cells  are  very  thin- walled  and 
contain   a   considerable    amount  of   finely   granulated   matter. 
Towards  the  pointed  end  the  fibre  becomes  colorless,  and  shows 
distinct   fibrous   fissures;     the   medullary    cylinder   disappears, 
but  the  epidermis  is  not  altered.     The  chief  difference  between 
these  hairs  and  the  beard-hairs  of  the  goat  is  that  in  the  former 
the  medullary  cells  consist  of  only  a  single  series,  and  are  very 
thin-walled,  and  are  also  frequently  isolated  from  one  another, 
while  they  are  filled  with  finely  granulated  matter.* 

2.  Soft,    fine,     beard-hairs    possessing     the    same    general 
structure  as  the  foregoing,  but  not  so  thick,  the  neck  of  the  hair 
being  75  [L  in  diameter  and  not  possessing  any  medulla.     Above 
this  the  medullary  cylinder  consists  of  very  thin-walled  cells 
arranged  in  isolated  .groups;    the  epidermal  scales  overlap  one 
another  and  are  almost  cylindrical,  are  narrow,  and  with  finely 
serrated   edges.     About   i    cm.   from   the  base   the  medullary 
cylinder  becomes  discontinuous   and  breaks  up  into  isolated 
medullary  cells,  which  continue  until  the  middle  of  the  fibre 
is   reached,    where    they   disappear   completely;     towards   the 
pointed  end  of  the  fibre  they  reappear  and  again  become  a 
continuous  cylinder,  consisting  of  only  a  single  series  of  cells, 

*  Cow-hair  may  be  distinguished  from  goat-hair  by  the  number  of  epidermal 
scales,  by  the  folds  in  the  medullary  canal,  and  by  the  single  row  of  cells  in  the 
medulla.  The  medulla  does  not  extend  to  the  apex,  which  is  also  usually  devoid 
of  epidermis. 


MINOR  HAIR  FIBRES 


101 


however.  These  are  well  filled  with  a  dark  medullary 
substance. 

3.  Very  fine  soft  wool-hairs,  free  from  medulla,  and  at 
most  only  i  to  4  cm.  in  length,  and  frequently  only  20  [L  in 
thickness.  The  epidermal  scales  are  rough,  causing  the  edge 
of  the  fibre  to  be  uneven  and  have  a  serrated  appearance.  The 
hairs  also  show  frequent  longitudinal  fibrous  fissures. 

Calf-hair  has  the  same  general  structure  and  appearance, 
though  there  is  a  greater  amount  of  soft  wool-hairs  present. 

As  cow-hair  is  at  times  to  be  met  with  in  admixture  with 
wool  as  an  adulterant  of  the  latter,  the  following  method  of 
distinguishing  between  the  two  devised  by  Hanausek  is  of 
interest.  The  microchemical  reaction  of  cow-hair  with  a  warm 


FIG.  30. — A,  Hair  of  Leicester  wool  in  water;   B,  Same  after  warming  in  potash; 
C,  Cow-hair  after  warming  in  potash.     (After  Hanausek.) 

solution  of  potash  is  very  similar  to  that  of  goat-hair  (see  p.  90) 
since  in  both  fibres  the  medullary  cells  are  transversely  elongated 
and  arranged  parallel  to  one  another.  An  important  dis- 
tinction from  goat-hair,  however,  is  the  presence  of  transverse 
air-spaces.  Fig.  30  shows  the  comparison  between  sheep's 
wool  and  cow-hair. 

10.  Minor  Hair  Fibres. — (a)  Horse-hair  has  a  diameter  of 
80  to  100  [L  and  a  length  of  i  to  2  cm.  (see  Fig.  31).  Like 
cow-hair,  it  also  occurs  in  a  variety  of  different  colors.  Horse- 
hair is  more  lustrous  than  the  foregoing,  however,  and  though 
when  viewed  under  the  microscope  the  ends  of  the  fibre  are 
irregular  and  often  forked,  they  taper  off  to  points.  The 
medullary  cylinder  is  rather  large,  occupying  about  two-thirds 
of  the  diameter  at  the  base  of  the  fibre  and  tapering  to  about 


102  THE  TEXTILE  FIBRES 

one-fourth  of  the  diameter  at  the  free  end.  The  medulla 
consists  of  one  to  two  rows  of  very  narrow  leaf-shaped  cells. 
Isolated  medullary  cells  are  of  frequent  occurrence,  especially 
at  the  point.  The  cortical  layer  frequently  contains  numerous 
short  orifices  or  fissures.  These  remarks  refer  to  the  body- 
hairs  of  the  horse;  the  hairs  of  the  tail  and  mane  are  much 
longer,  reaching  from  several  inches  to  a  foot  or  more.  They 


FIG.  31. — Horse-hair.     (Xioo.)     (Micrograph  by  author.) 

find  but  little  use  in  ordinary  textiles,  but  are  much  used  as 
stuffing  materials  in  the  manufacture  of  upholstery. 

(b)  Cat-hair  varies  in  diameter  from  14  to  34  [L  and  in 
length  from  i  to  2  cm.  The  fibres  occur  in  a  variety  of  colors 
and  have  a  good  lustre.  The  ends  are  quite  regular  and  very 
pointed.  The  medullary  canal  contains  a  single  series  of  regular 
cells  occupying  one-half  to  three-fifths  of  the  diameter  of  the 
fibre.  The  cortical  layer  is  well  developed,  and  its  inner  face 
is  grooved  so  as  to  fit  over  the  medullary  cells.  There  is  a  thin 
irregular  epidermis  which  envelops  the  fibre  (see  Fig.  32). 


MINOR   HAIR  FIBRES 


103 


(c)  Rabbit-hair  fibres  are  usually  light  brown  in  color  and 
measure  from  34  to  120  pi  in  diameter,  and  from  i  to  2  cm. 
in  length.  The  medullary  canal  is  filled  with  several  series  of 
cells,  quadrangular  in  shape  and  with  thin  walls.  They  are 
also  arranged  in  a  very  regular  manner.  By  careful  observa- 
tion spiral  striations  may  be  noticed  on  the  finer  fibres.  The 
epidermal  scales  are  very  thick  and  their  forward  edges  ter- 


FIG.  32.— Hairs  of  Cat.     (X3SO.) 
A,  fine-wool  hair;  B,  coarse  beard-hair.     (Micrograph  by  author.) 


minate  in  a  sharp  point  (see  Fig.  33).  Each  scale  is  placed 
cornucopia-like  into  the  next  lower  one,  and  is  drawn  out  into 
i  to  3  large  waves.  At  the  base  of  the  fibre  the  medulla  con- 
sists of  a  single  row  of  cells,  above  the  middle  this  increases 
to  2  to  4  rows,  and  further  along  the  fibre  the  number  of  rows 
of  cells  increases  up  to  8,  when  the  hair  becomes  very  wide. 
Like  most  pelt-hairs,  the  fibres  are  somewhat  flattened  at  the 
base,  and  quite  so  at  their  broadest  part.  The  cortical  layer 


104 


THE  TEXTILE  FIBRES 


is  only  apparent  towards  the  point  where  the  medulla  ceases. 
The  fine  wool-hairs  of  the  rabbit  are  much  thinner  than  the 


FIG.  33. — Rabbit-hair.     (X350.)     A,  wool-hair;  B,  beard-hair. 
(Micrograph  by  author.) 

above,  the  greatest  thickness  being  about  20  pi.  Otherwise 
they  correspond  in  structure  to  that  part  of  the  above  fibre 
near  the  base. 


CHAPTER  VI 

SILK:  ITS  ORIGIN  AND  CULTIVATION 

1.  General    Considerations. — The    silk   fibre    consists   of   a 
continuous  thread  which  is  spun  by  the  silkworm.     The 'worm 
winds   the  fibre  around  itself  in   the  form  of  an  enveloping 
cocoon  before  it  passes  into  the  chrysalis  or  pupal  state.     The 
cocoon  is  ovoid  in  shape  and  is  composed  of  one  continuous 
fibre,  which  varies  in  length  from  350  to  1200  meters  (400  to 
1300  yards),  and  has  an  average  diameter  of  0.018  mm.     In 
the  raw  state  the  fibre  consists  of  a  double  thread  cemented 
together  by  an  enveloping  layer  of  silk-glue,  and  is  yellowish 
and  translucent  in  appearance.     When  boiled  off  or  scoured 
these  double  threads  are  separated,  and  the  silk  then  appears 
as  a  single  lustrous  and  almost  white  fibre.     Unlike  both  wool 
and  cotton,  silk  is  not  cellular  in  structure,  and  is  apparently  a 
continuous   filament   devoid    of   structure.     Hohnel,    however, 
believes  that  the  silk  fibre  is  not  so  simple  in  structure  as  would 
at  first  be  believed.     The  surface  of  the  fibre  frequently  shows 
faint   striations,   which  may  be   rendered   more   apparent  by 
treatment   with   chromic   acid.     Also   by   saturating   the    silk 
with  moderately  concentrated  sulphuric  acid  and  drying,  then 
heating  to  80°  to  100°  C.,  the  fibre  will  be  disintegrated  into 
small  filaments,  which  would  seem  to  indicate  that  it  was  made 
up  of  a  number  of  minute  fibrils  firmly  held  together. 

2.  The  Silkworm. — The  silkworm  is  a  species  of  caterpillar, 
and  though  there  are  quite  a  number  of  the  latter  which  possess 
silk-producing  organs,   the  number  which  secrete  a  sufficient 
quantity  of  the  silk  substance  to  render  them  of  commercial 
importance  is  rather  limited.     The  true  silkworms  all  belong 
to  the  general   class  Lepidoptera,  or  scale-winged   insects,  and 

105 


106  THE  TEXTILE  FIBRES 

more  specifically  to  the  genus  Bombyx.  The  principal  species 
is  the  Bombyx  mori,  or  mulberry  silkworm,  which  produces 
by  far  the  major  portion  of  the  silk  that  comes  into  trade.* 
The  silk  industry  appears  to  have  had  its  origin  in  China,  and 
historically  it  dates  back  to  about  2700  years  B.C.  In  its  early 
history  it  is  said  that  the  art  of  cultivating  the  silkworm  and 
preparing  the  fibre  for  use  was  a  strictly  guarded  secret  known 
only  to  the  royal  family.  Gradually,  however,  it  spread 
through  other  circles  and  soon  became  an  important  industry 
distributed  universally  throughout  China.  The  Chinese  monop- 
olized the  art  for  over  three  thousand  years,  but  during  the 
early  period  of  the  Christian  era  the  cultivation  of  the  silk- 
worm (or  sericulture)  was  introduced  into  Japan.  It  also 
gradually  spread  throughout  central  Asia,  thence  to  Persia 
and  Turkey.  In  the  eighth  century  the  Arabs  acquired  a 
knowledge  of  the  silk  industry,  which  soon  spread  through  all 
the  countries  influenced  by  the  Moorish  rule,  including  Spain, 
Sicily,  and  the  African  coast.  In  the  twelfth  century  we  find 
sericulture  practised  in  Italy,  where  it  slowly  developed  to  a 
national  industry.  In  France  sericulture  appears  to  have  been 
introduced  about  the  thirteenth  century,  but  it  was  not  until 
the  reign  of  Louis  XIV  that  it  assumed  any  degree  of  importance. 
In  more  recent  times  experiments  have  been  made  on  the  cultiva- 
tion of  the  silkworm  in  almost  every  civilized  country.f 

Mr.  Samuel  Whitmarsh,  about  1838,  appears  to  have  been 
the  first  to  attempt  sericulture  in  America.  He  cultivated  the 
Motus  multicaulis  in  Pennsylvania,  but  the  experiment  proved 
to  be  a  failure.  In  later  years  there  have  been  many  attempts 
to  introduce  the  industry  of  sericulture  into  the  United  States, 
and  it  has  been  satisfactorily  demonstrated  that  good  silk 
can  be  raised  in  this  country,  more  especially  in  the  Southern 
States.  The  failure  of  the  industry  has  not  been  due  to  lack 

*  Wardle  (Tussur  Silk,  p.  40)  gives  a  list  of  several  hundred  species  of  Lepi- 
doptera  that  yield  silk. 

f  In  1903  the  production  of  silk  cocoons  in  Servia  amounted  to  345,000  pounds. 
The  government  annually  distributes  large  quantities  of  eggs  to  encourage  the 
industry. 


SILK:    ITS   ORIGIN  AND   CULTIVATION  107 

of  proper  climatic  conditions,  but  simply  to  the  high  cost  of 
labor  as  compared  with  Oriental  labor.  With  respect  to  the 
amount  of  raw  material  consumed,  the  United  States  stands 
first  among  the  silk  manufacturing  countries  of  the  world, 
though  in  the  value  of  its  manufactures  it  ranks  second.* 

According  to  the  number  of  the  generations  they  produce 
in  a  year,  the  Bombyx  mori  are  divided  into  two  classes:  the 
members  of  the  one  reproduce  themselves  several  times  annually, 
and  are  termed  polyvoltine;  their  cocoons  are  small  and  coarse. 
The  other  worms  have  only  one  generation  in  a  year,  and  hence 
are  termed  annual.  The  cocoons  of  the  latter  are  much  superior 
to  those  of  the  former.  The  cultivation  of  the  silkworm  starts 
with  the  proper  care  and  disposition  of  the  eggs.f  With  the 
annual  worms  there  elapse  about  ten  months  between  the 
time  the  eggs  are  laid  and  their  hatching.  The  hatching  only 

*  With  the  possible  exception  of  China,  for  which  no  complete  statistics  are 
available,  the  United  States  is  now  the  largest  silk  manufacturing  country  in 
the  world.  In  1909  the  imports  of  raw  silk  amounted  to  $75,000,000,  and  the 
value  of  the  manufactured  products  of  the  silk  industry  for  that  year  were 
$196,425,000.  The  imports  of  silk  materials  into  the  United  States  for  the  year 
1912  were  as  follows: 

Pounds.  Value. 

Cocoons 82,456  $51,073 

Raw  silk  reeled  from: 

France.  .  91,387  334,66o 

Italy 2,058,456  7,467,623 

China 4,776,506  11,399,407 

JaPan .14,493,131  47,3i6,33i 

Other  countries 190,040  655,361 


Total 21,609,520  $67,173,382 

Manufactures  of  silk 27,204,364 

t  There  are  two  kinds  of  silkworm  culture:  One  for  production  and  one 
for  breeding.  The  object  in  the  first  case  is  to  get  the  greatest  yield  of  cocoons, 
and  with  a  little  training  may  be  carried  on  by  any  one  of  ordinary  intelligence. 

The  object  in  culture  for  breeding  is  to  secure  eggs  free  from  hereditary 
taint  of  disease,  and  experts  only  can  be  depended  on  for  this  culture.  Besides 
a  careful  physiological  examination  throughout  the  rearing,  the  body  of  the  mother 
moth  is  microscopically  tested  after  death,  and  her  eggs  are  not  retained  if  signs 
of  disease  are  discovered.  In  this  way  the  birth  of  healthy  worms  is  insured. 
Pasteur  first  applied  this  method  of  selecting  silkworm  eggs,  and  thus  checked 
the  plague  (pebrine)  which  was  rapidly  destroying  silkworm  culture  in  Europe. 
(Silkworm  Culture,  Bull.  U.  S.  Dept.  Agric.) 


108 


THE  TEXTILE  FIBRES 


takes  place  after  the  eggs  have  been  exposed  to  the  cold  for 
some  time  and  are  subsequently  subjected  to  the  influence  of 
heat.  When  the  eggs'  are  laid  by  the  siik-moth  they  are 
received  on  cloths,  to  which  they  stick  by  virtue  of  a  gummy 
substance  which  encloses  them.  For  the  first  few  days  they 
are  hung  up  in  a  room,  the  air  of  which  is  kept  at  a  certain  degree 
of  humidity — about  semi-saturation.  Then  comes  a  period 


FIG.  34. — Showing  Different  Stages  in  Growth  of  Silkworm. 

A,  silkworm  in  fifth  period,  full  size;  B,  moth  or  butterfly;   C,  chrysalis,  or  pupa; 
D,  eggs  of  moth;  E,  diagram  showing  cocoon  and  method  of  winding. 

of  hibernation,  during  which  the  eggs  are  kept  in  a  cool  place; 
at  present  artificial  refrigeration  is  resorted  to  in  many  estab- 
lishments. The  period  of  hibernation  lasts  about  six  months. 
After  this  comes  the  period  of  incubation,  in  which  the  embryo 
is  gradually  developed  into  a  worm  and  the  egg  is  hatched. 
The  hatching  usually  takes  place  in  heated  compartments, 
in  which  the  temperature  is  carefully  regulated.  The  period 


SILK:    ITS  ORIGIN  AND  CULTIVATION 


109 


of  incubation  occupies  about  thirty  days,  though  this  time 
has  been  shortened  considerably  by  certain  artifices,  such  as 
the  action  of  electric  discharges.  Twenty-five  grams  of  eggs 
will  yield  about  36,000  worms  on  hatching.  The  caterpillar, 
on  first  making  its  appearance,  is  about  3  mm.  long,  and  weighs 
approximately  0.0005  gram.  Its  growth  and  development 
proceed  with  extraordinary  rapidity,  and  during  its  short 
existence  it  undergoes  a  number  of  very  curious  transformations. 
Under  normal  conditions  there  elapse  thirty-three  to  thirty-four 
days  between  the  time  of  the  hatching  of  the  egg  and  the  com- 
mencement of  the  spinning  of  the  cocoon.  During  this  time 


r 

i  W 


IB 


14 


15 


FIG.  35 —The  Silkworm. 

i,  head;    2-10,  12,  rings;  n,  horn;'  13,  articulated  legs;  14,  abdominal  or  false 
legs;  15,  false  legs  on  last  ring. 

the  worm  sheds  its  skin  four  times,  and  these  periods  of  moulting 
divide  the  life-history  of  the  worm  into  five  periods.*  Almost 
immediately  after  being  hatched  the  worms  commence  to 
devour  mulberry  leaves  with  great  avidity,  and  continue  to 
eat  throughout  the  five  periods,  though,  when  about  to  shed 
their  skins,  they  stop  eating  for  a  time  and  become  motionless. 

*  The  length  of  time  occupied  in  these  different  ages  approximates  as  follows: 
ist,  from  birth  to  first  moult,  5  to  6  days. 
2d,  from  first  to  second  moult,  4  days. 
3d,  from  second  to  third  moult,  4  to  5  days. 
4th,  from  third  to  fourth  moult,  5  to  7  days. 
5th,  from  fourth  moult  to  maturity,  7  to  12  days. 


110  THE  TEXTILE  FIBRES 

The  size  and  weight  of  the  caterpillars  increase  with  remarkable 
rapidity;  during  the  fifth  period  they  reach  their  greatest 
development,  measuring  from  8  to  9  cm.  in  length  (see  Fig. 
35)  and  weighing  from  4  to  5  grams,  and  after  thus  maturing 
they  begin  to  diminish  in  weight.  The  following  table  by 
Vignon  shows  the  relative  weights  of  the  silkworm  during  the 
different  stages  of  its  existence.  The  figures  refer  to  the  weight 
of  36,000  worms. 

Grams. 

Eggs 25 

Worms  (36,000) 17 

First  period  (5  to  6  days) 255 

Second  period  (4  to  5  days) !>598 

Third  period  (6  to  7  days) 6,800 

Fourth  period  (7  to  8  days) 27,676 

Fifth  period  (n  to  12  days) 161,500 

At  maturity 131,920 

Cocoons 76,250 

Chrysalis  alone 66,300 

Butterflies,  half  of  each  sex 99,865 

Thus  we  see  that  in  less  than  forty  days  the  weight  of  the 
silkworm  increases  almost  10,000  times. 

When  the  worm  has  reached  the  limit  of  its  growth,  it 
ceases  to  eat,  and  commences  to  diminish  in  size  and  weight. 
The  time  is  now  ready  for  the  spinning  of  its  cocoon ;  the  worm 
perches  on  the  twigs  so  disposed  to  receive  it  and  exudes  a  vis- 
cous fluid  from  the  two  glands  in  its  body  wherein  the  silk 
secretion  is  formed.  The  liquid  flows  through  two  channels 
in  the  head  of  the  worm  into  a  common  exit-tube,  where  also 
flows  the  secretion  of  two  other  symmetrically  situated  glands 
which  cements  the  two  threads  together.  I  Consequently,  the 
thread  of  raw  silk  is  produced  by  four  glands  in  the  worm; 
the  two  back  ones  secrete  the  fibroin  which  gives  the  double 
silk  fibre,  while  the  two  front  glands  secrete  the  silk-glue  or 
sericin  which  serves  as  an  integument  and  cementing  substance.^ 

*  According  to  Bolley  the  glands  in  the  silkworm  which  secrete  the  fibre- 
producing  liquids  contain  only  glutinous,  semi-fluid  fibroin  without  admixture 
with  sericin,  the  latter  compound  being  a  product  of  the  subsequent  oxidation 
of  the  fibroin  by  the  air. 


SILK:    ITS  ORIGIN  AND  CULTIVATION 


111 


On  emerging  from  the  spinneret  in  the  head  of  the  worm  the 
fibre  coagulates  on  contact  with  the  air.* 

3.  The  Cocoon. — The  worm  weaves  this  thread  around 
itself,  layer  after  layer,  until  the  cocoon  or  shell  is  gradually 
built  up.  It  requires  about  three  days  for  the  completion 
of  the  cocoon.  First  a  net  is  formed  to  hold  the  cocoon  which 
is  to  be  spun,  then  the  regular  spinning  begins  and  the  form 
of  the  cocoon  is  designed.  It  is  calculated  that  with  its  head 
alone  the  silkworm  makes  69  movements  every  minute,  describ- 
ing arcs  of  circles,  crossed  in  the  form  of  the  figure  8.  Mean- 
while the  web  grows  closer  and  the  veil  thickens,  and  in  about 
72  hours  the  worm  is  completely  shut  up  in  .its  cocoon,  which 


FIG.  36. — Cross-section  of  Silk-cocoon. 

,  silkworm  at  completion  of  cocoon;  6,  after  development  of  chrysalis  with  cast- 
off  skin  of  larva  beneath. 


serves  it  as  a  protective  covering,  f  After  finishing  the  winding 
of  its  cocoon,  the  enclosed  silkworm  undergoes  a  remarkable 
transformation,  passing  from  the  form  of  a  caterpillar  into 
an  inert  chrysalis  or  pupa,  from  which  condition  it  rapidly 
develops  into  a  butterfly,  which  then  cuts  an  opening  through 

*  The  contents  of  the  glands  of  the  silkworm  have  been  the  subject  of  study 
in  a  peculiar  manner  by  Chappe.  He  triturated  the  glutinous  matter  with  about 
one-third  its  weight  of  water,  and  thus  obtained  a  liquid  from  which  he  was 
enabled  to  blow  variously  shaped  vessels  of  a  very  permanent  character.  (Ann. 
de  Chim.,  vol.  n,  p.  113.) 

t  Silkworm  Culture,  Bull.  U.  S.  Dept.  Agric. 


112 


THE  TEXTILE   FIBRES 


the  cocoon  and  flies  away.  The  worm  in  spinning  the  cocoon 
leaves  one  end  less  dense,  so  that  the  threads  open  freely  to 
permit  the  egress  of  the  moth.  By  the  aid  of  an  alkaline 
fluid  the  moth  softens  and  parts  the  threads  and  liberates 
itself.  As  the  integrity  of  the  cocoon-thread  would  be  destroyed 
by  the  escape  of  the  butterfly  and  hence  lose  much  of  its  value, 
it  is  desirable  that  the  development  of  the  chrysalis  be  stopped 
before  it  proceeds  too  far,  and  this  is  accomplished-  by  killing 


FIG.  37. — The  Silk-moth,     a,  male;  b,  female. 

it  by  a  heat  of  from  70°  to  80°  C.  or  by  live  steam.  The  cocoons 
at  this  stage  weigh  from  1.25  to  2.5  grams  each,  and  of  this 
15  to  16  per  cent  is  silk  fibre.  The  proportion  of  silk  in  a  cocoon 
varies  according  to  the  race  and  also  to  the  regimen  to  which 
the  worm  has  been  subjected.  The  average  normal  cocoon  at 
the  time  it  is  sold  is  thus  composed. 

Per  Cent. 

Water 68 . 2 

Silk 14-3 

Web  and  veil 0.7 

Chrysalis 16 . 8 


SILK:    ITS   ORIGIN  AND  CULTIVATION  113 

However,  only  8  to  10  per  cent  is  available  for  silk  filaments, 
the  remainder,  6  to  7  per  cent,  constituting  waste  and  broken 
threads,  and  is  utilized  for  spun  silk. 

There  are  several  different  varieties  of  waste  silk,  as  follows: 

1.  The    refuse    obtained    in    raising    the    silkworm,    called 
watt  silk  in  commerce.     Owing  to  the  scientific  methods  of 
silk-culture  in  Europe,  the  amount  obtained  from  this  source 
is  very  small.     China,  however,  exports  a  large  amount  yearly. 
This  material  contains  about  35  per  cent  of  pure  silk,  and  is 
the  poorest  grade  of  waste  silk  on  account  of  its  irregularity. 

2.  The  irregularly   spun  and   tangled   silk   on   the   outside 
of  the  cocoon,  called  floss  silk  or  frisons.     It  comprises  from 
25  to  30  per  cent  of  the  entire  cocoon,  and  is  valuable  owing 
to  its  purity  and  fine  quality. 

3.  The  residue  of  the  cocoon  after  reeling;    this  forms  an 
inner  parchment-like  skin,   and  in  commerce  goes  under  the 
name  of  ricotti,  wadding,  neri,  galettame,  basinetto,  etc. 

4.  Cocoons  imperfect  from  various  causes,   such  as  being 
punctured  by  the  worms,  becoming  spotted  by  pupa  breaking, 
etc.     These    are   known    as    cocons,    perces,    piques,    tarmate, 
rugginose,    etc.     It    forms    a    valuable   material    for   floss-silk 
spinning. 

5.  Double  cocoons,  which,  in  spite  of  the  difficulty  in  reel- 
ing, were  formerly  used  for  special  purposes.     Now  such  cocoons 
are  converted  into  waste  which  is  known  as  strussa. 

6.  Waste  obtained  in  reeling  the  cocoons,  known  as  frisonnets. 

7.  A  great  variety  of  wild  silks,  which,  for  the  most  part, 
cannot  be  reeled,  and  are,  therefore,  first  converted  into  waste. 
A  large  quantity  of  wild  silk,  even  though  it  can  be  reeled, 
is  torn  up  for  waste. 

8.  Waste  made  by  reeling,   spooling,   and  other  processes 
of  working  silk. 

Silk  shoddy  resembles  wool  shoddy  in  origin,  consisting  of 
recovered  fibres  from  manufactured  silk  goods.  It  nearly 
always  contains  isolated  fibres  of  both  wool  and  cotton,  and 
frequently  mixtures  of  different  kinds  of  silk.  There  may 
also  occur  boiled-off,  soupled,  and  raw  silk,  and  mixtures  of 


114 


THE  TEXTILE   FIBRES 


organzine  and  spun  silk.  Different  colors  are  also  usually 
present.  The  fibres,  as  a  rule,  are  quite  short,  being  about 
a  centimeter  in  length.  Due  to  these  components,  silk  shoddy 
is  comparatively  easy  to  recognize  under  the  microscope. 

As  to  the  thickness  of  the  filaments  of  silk  in  the  cocoon, 
Haberlandt  furnishes  the  following  data. 


Species. 

Exterior  Layer 
of  Cocoon. 

Middle 
Layer. 

Interior 
Layer. 

Yellow  Milanais  
Yellow  French  
Green  Japan 

0.030  mm. 
0.025    " 
o  030    '  ' 

0.040  mm. 

o-035    " 
o  040    '  ' 

0.025  mm. 
0.025    " 

White  Japan  
Bivoltin  worms  .  .  . 

O.O2O     " 

O    O2s      " 

o  .  030    '  ' 
o  03  ^    '  ' 

0.017    " 
o  020    '  ' 

^•<-\50 

The  double  silk  fibre  as  it  exists  in  the  cocoon  is  known  as 
the  bave,  and  the  single  filaments  are  called  brins. 

The  size  of  the  single  silk  filament  as  it  comes  from  the 
cocoon  averages  i\  denier.*  The  following  table  gives  the 
approximate  size  of  filaments  of  mulberry  silk  from  different 
countries. 


Weight  of 

>oo  Meters. 

Country. 

In 
Deniers. 

In 
Milligrams. 

Spain  

3   O 

163 

France 

2   6 

n8 

Italy  

2  .A 

128 

Syria 

,          24. 

128 

Caucasus  

2  .  3 

125 

Brousse  

2    2 

117 

Tapan 

2    I 

I  I  3 

China 

2    O 

1  08 

Bengal  

I  .  2 

64 

4.  Diseases  of  the  Silkworm. — The  silkworm  is  particularly 
liable  to  contract  various  diseases,  which  become  more  or  less 
epidemic  in  character.  In  the  early  history  of  sericulture  in 

*  See  p.  583. 


SILK:    ITS  ORIGIN  AND  CULTIVATION  115 

Europe  the  industry  was  frequently  threatened  with  almost 
total  destruction  by  the  widespread  ravages  of  certain  diseases 
of  the  silkworm.  The  French  chemist  Pasteur  devoted  much 
attention  to  this  subject  and  succeeded  in  devising  means  of 
avoiding  or  preventing  almost  all  such  diseases.  The  principal 
diseases  of  the  silkworm  are  the  following. 

(a)  Pebrine*    Worms   afflicted   with   this   disease   develop 
slowly,  irregularly,  and  very  unequally.     Black  spots  are  the 
most  marked  outward  characteristics:    the  internal  signs  are 
oval    corpuscles    visible    only    under    the    microscope.     There 
appears  to  be  no  remedy  for  this  disease,  but  Pasteur  found 
it  could  be  prevented  by  a  microscopical  selection  of  the  eggs, 
and  at  the  present  day  it  causes  but  little  trouble  among  silk- 
growers. 

(b)  Flacherie  (or  flaccidity)  is  at  present  the  most  dreaded 
disease    among   European    silkworms.     It   usually   affects   the 
worm  after  the  fourth  moult,  or  even  while  spinning.     With- 
out apparent  cause  the  worms  begin  to  languish  and  shortly 
die.     After  death  they  turn  black  in  color  and  emit  a  dis- 
agreeable odor.     Flacherie  is  apparently  a 'form  of  indigestion, 
and  may  be  induced  by  micro-organisms  in  the  intestinal  canal 
of  the  worm.     Contagion  is  usually  prevented  by  dipping  the 
eggs  in  a  solution  of  copper  sulphate,  and  as  the  micro-organisms 
causing  flacherie  persist  alive  from  year  to  year,  very  careful 
fumigation  must  be  instituted  whenever  this  disease  develops. 

(c)  Gattine  shows  itself  externally  by  indifference  of  the  worm 
to  food,  torpor,  and  generally  emaciation.     It  usually  affects 
the  worm  in  the  early  ages,  though  it  is  sometimes  associated 
with   flacherie.     The    best   preventive    against    both   flacherie 
and  gattine  is  a  careful  selection  of  healthy  eggs. 

(d)  Calcino  (or  muscardine)   at  first  does  not  exhibit  any 
external  characteristics,  but  the  vitality  of  the  worm  is  slowly 
impaired  and  it  feeds  and  moves  but  slowly.     The  body  becomes 

*  Between  1833  and  1865  the  annual  crop  of  cocoons  in  France  was  reduced 
by  pebrine  from  57,200,000  Ibs.  to  8,800,000  Ibs.  It  was  first  noticed  in  epi- 
demic form  in  France  in  1845,  but  since  then  has  spread  throughout  Asia  Minor 
and  the  Orient. 


116 


THE  TEXTILE   FIBRES 


reddish  in  color,  and  gradually  contracts  and  loses  its  elasticity, 
and  the  worm  usually  dies  20-30  hours  after  the  first  symptoms 
of  the  disease.  The  dead  body  dries  up  and  becomes  covered 
with  a  white  chalk-like  efflorescence.  The  disease  is  caused 
by  a  minute  fungus,*  the  spores  of  which  take  root  in  the  body 
of  the  worm,  and  finally  fill  the  entire  body.  Calcino  is  the 
most  contagious  of  the  silkworm  diseases,  and  its  appearance 
should  be  promptly  checked  by  careful  fumigation  with  burning 
sulphur. 


B  C 

FIG.  38. — Diseased  Silkworms. 

A,  worm  afflicted  with  flacherie;    5,  worm  emaciated  by  gattine;    C,  calcinated 
worm.     (After  Silkworm  Culture.} 

(e)  Grasserie  shows  itself  by  the  worms  becoming  restless, 
bloated,  and  yellow  in  color,  and  when  punctured  they  exude 
a  fetid  matter  filled  with  minute  granular  crystals.  The  disease 
is  not  caused  by  microbes,  hence  is  neither  contagious  nor 
hereditary.  Its  chief  cause  is  mismanagement  of  the  worms 
at  moulting  periods  and  uneven  feeding. 

5.  Wild  Silks. — Besides  the  Bombyx  mori,  or  mulberry 
silkworm,  there  are  other  associated  varieties  of  caterpillars, 

*  There  are  two  varieties  of  this  fungus:  Botrytis  bassiana  and  B.  tevella. 
The  white  chalk-like  appearance  of  the  dead  worm  is  caused  by  the  branches 
of  the  fungus  fructifying  on  the  surface,  and  the  fruit  bursting  envelops  the  worm 
with  innumerable  spores  resembling  a  white  powder. 


SILK:    ITS  ORIGIN  AND   CULTIVATION  117 

which  also  produce  silk  in  sufficient  quantity  to  be  of  con- 
siderable commercial  importance.  Due  to  the  fact  that  such 
silkworms  are  not  capable  of  being  domesticated  and  artificially 
cultivated  like  the  mulberry  worms,  the  silk  obtained  from  them 
is  called  wild  silk.  Of  this  latter  there  are  several  commercial 
varieties,  of  which  the  most  important  are  here  given.* 

*  Spider  Silk. — Attention  has  recently  been  drawn  to  the  possibility  of  obtain- 
ing silk  from  a  species  of  spider  chiefly  found  in  Madagascar.  The  spider  is  known 
as  Nephila  Madagascar  iensis.  The  egg-receptacle  is  a  silky  cocoon  about  one  inch 
in  diameter  and  of  a  yellow  color,  but  turning  white  after  several  months'  exposure 
to  the  air.  The  female  spider  alone  produces  the  silk  and  is  about  two  and  a  half 
inches  long.  The  silk  is  reeled  off  from  the  spider  five  or  six  times  in  the  course 
of  a  month,  after  which  it  dies,  having  yielded  about  4000  yards.  The  reeling 
is  done  by  native  girls;  about  one  dozen  spiders  are  locked  in  a  frame  in  such 
a  manner  that  on  one  side  protrudes  the  abdomen,  while  on  the  other  side  the 
head,  thorax,  and  legs  are  free.  The  ends  of  their  webs  are  drawn  out,  collected 
into  one  thread,  which  is  passed  over  a  metal  hook,  and  the  reel  is  set  in  motion 
by  a  pedal.  The  extraction  of  the  web  does  not  apparently  inconvenience  the 
spider.  The  cost  of  the  material  is  high,  as  55,000  yards  of  19  strands  thick- 
ness weighs  only  386  grains,  and  one  pound  of  the  silk  is  worth  $40.  At  the 
Paris  Exposition  of  1900,  a  fabric  was  shown,  18  yards  long  by  18  inches  wide, 
containing  100,000  yards  of  spun  thread  of  24  strands,  the  product  of  25,000 
spiders.  It  was  golden  yellow  in  color.  Spinning  spiders  are  also  known  in 
Paraguay,  Venezuela,  and  other  countries.  (See  Jour.  Soc.  Arts,  vol.  53,  p.  620.) 
The  threads  spun  by  the  Nephila  Madagascar  iensis  closely  resembles  ordinary 
silk  in  external  appearance.  Each  spider  produces  about  150-600  metres  of 
fibre.  The  silk  has  an  orange-yellow  color,  which  becomes  intensified  by  alkalies 
and  is  destroyed  by  acids.  It  differs  from  ordinary  silk  principally  in  its  small 
amount  of  silk-glue  (or  water-soluble  substances).  According  to  Fischer  (Zeit. 
physiol.  Chem.,  1907,  p.  126)  spider  silk  gave  the  following  products  when 
hydrolyzed  with  acid: 

Per  Cent. 

Glycocoll 25 . 13 

^-alanin. . 23 . 40 

/-leucin i .  76 

Prolin 3 . 68 

/-tyrosin 8 . 20 

d-glutaminic  acid 1 1 .  70 

Diamino  acids 5 .  24 

Ammonia i .  16 

Fatty  acids o .  59 

Glutaminic  acid,  which  is  present  in  rather  a  large  amount  in  spider  silk,  has 
not  been  found  in  ordinary  silk.  Spider  silk,  on  ignition,  gave  0.59  per  cent 
of  ash. 


118  THE   TEXTILE  FIBRES 

Anther  aa  yama-mai,  a  native  of  Japan,  is  a  green-colored 
caterpillar  which  feeds  on  oak-leaves.  Its  cocoon  is  large  and 
of  a  bright  greenish  color.  The  silk  bears  a  close  resemblance 
to  that  of  the  Bombyx  mori,  but  is  not  as  readily  dyed  and 
bleached  as  the  latter. 

Anther  aa  pernyi  is  a  native  of  China;  besides  growing 
wild,  it  has  been  domesticated  to  some  extent.  This  worm  also 
feeds  on  oak-leaves,  but  is  of  a  yellow  color.  Its  cocoon  is  quite 
large,  averaging  over  4  cm.  in  length,  and  is  of  a  yellowish  to 
a  brown  color. 

Anther  &a  assama  is  a  native  of  India;  it  gives  a  large  cocoon 
over  45  mm.  in  length. 

Anther  eta,  mylitta  is  another  Indian  variety,  and  furnishes 
the  so-called  tussah  silk,  though  this  term  has  also  been  applied 
in  a  general  manner  to  all  varieties  of  wild  silk.  The  worms 
feed  on  the  leaves  of  the  castor-oil  plant,  and  give  very  large 
cocoons,  reaching  50  mm.  in  length  and  30  mm.  in  diameter. 
The  fibre  is  much  longer  than  from  the  cocoon  of  the  B.  mori, 
and  Varies  from  600  to  2000  yards  in  length.  The  color  of 
tussah  silk  varies  from  a  gray  to  a  deep  brown.* 

Another  variety  of  silkworm  which  is  to  be  found  both  in 
Asia  and  America  is  the  Attacus  ricini.  It  gives  a  very  white 
and  good  quality  silk,  the  production  and  value  of  which  is 
increasing  every  year.  It  is  known  as  Eria  silk.  The  structure 
of  the  fibre  much  resembles  that  of  tussah  silk.  A  species  of 
this  class,  known  as  Attacus  atlas,  is  perhaps  the  largest  moth 
known;  it  spins  open  cocoons  and  gives  the  so-called  Fagara, 
or  Ailanthus,  silk. 

There  is  a  silkworm  found  in  Uganda  and  other  parts  of 
Africa  belonging  to  the  Anaphe  species.  It  feeds  principally 
on  the  leaves  of  a  species  of  fig  tree.  The  caterpillars  construct 

*  Silbermann  classifies  the  varieties  of  wild  silkworms  as  follows: 

(1)  Those  with  closed  cocoons  containing  fairly  uniform  silk  threads  which 
can   be  reeled   without   much   difficulty:     (a)     Wild   mulberry   silkworms;     (6) 
Anther  aa  yama-mai;   (c)   Tussah  family;    (d)   Moonga  family;    (e)   Actias  family. 

(2)  Those  with  open  cocoons  containing  silk  threads  which  cannot  be  reeled: 
(a)  Attacus  family;  (b)  various  other  species. 

(3)  Various  species  of  Saturnidce,  as  yet  of  no  technical  value. 


SILK:    ITS  ORIGIN  AND  CULTIVATION  119 

large  nests  inside  of  which  they  form  their  cocoons  in  con- 
siderable numbers.  The  entire  nest  together  with  the  cocoons 
is  composed  of  silk,  and  the  whole  of  the  product  is  capable  of 
being  used  for  waste  silk.  In  southern  Nigeria  this  anaphe 
silk  is  used  by  the  natives  in  conjunction  with  cotton  for  making 
the  so-called  "  soyan  "  cloths. 

Wild  silk  is  much  more  difficult  to  unwind  from  the  cocoons 
than  that  of  the  mulberry  silkworm,  and  is  also  much 
darker  in  color.  As  the  individual  filaments  are  much  coarser 
than  those  of  mulberry  silk  the  former,  as  a  rule,  have  greater 
strength,  but  on  reduction  to  a  basis  of  equal  diameters,  the 
filaments  of  mulberry  silk  are  somewhat  stronger,  and  are  much 
more  difficult  to  dye  and  bleach. 

Tussah  (or  tussur)  silk,  as  well  as  other  wild  silks,  is  chiefly 
employed  for  making  pile-fabrics,  such  as  velvet,  plush,  and 
imitation  sealskin. 


CHAPTER   VII 

PHYSICAL   PROPERTIES  OF  SILK 

i.  The  Microscopy  of  the  Silk  Fibre. — Under  the  microscope 
raw  silk  exhibits  an  appearance  which  readily  distinguishes 
it  from  other  textile  fibres.  The  fibre  of  fibroin  when  purified 
from  adhering  sericin  is  seen  as  a  smooth  structureless  fila- 
ment, very  regular  in  diameter  and  very  transparent.  Occa- 
sionally constrictions  occur  in  the  fibre  as  well  as  swellings  or 
lumps.  The  two  brins  in  the  bave  of  raw  silk  give  beautiful 
colors  with  polarized  light  when  examined  microscopically. 
The  sericin  coating,  however,  appears  to  have  no  such  action. 
The  latter,  being  hard  and  brittle,  on  bending  develops  transverse 
cracks  which  are  very  apparent  under  the  microscope. 

The  fibre  of  Bombyx  mori  is  only  rarely  striated  longitudinally, 
and  when  such  striations  do  appear  they  always  run  parallel  to 
the  axis  of  the  fibre.  When  treated  with  dilute  chromic  acid 
very  fine  striations  are  caused  to  appear.  Wild  silks  often 
show  fibres  which  are  twisted  on  their  axes,  and  the  layer  of 
gum  is  usually  more  or  less  granular.  Anther  cea  mylitta  shows 
rather  frequent  oblique  striations,  and  does  not  exhibit  much 
play  of  color  with  polarized  light.  This  latter  characteristic 
is  also  true  of  Anther  aa  yama-mai.  The  other  silks  give  nice 
colors  with  polarized  light.  Silk  fibres  are  colored  a  deep  red 
with  alloxanthin;  fuchsin  also  gives  a  red  color.  On  treatment 
with  sugar  and  sulphuric  acid,  silk  is  first  colored  a  rose-red  and 
then  dissolves ;  hydrochloric  acid  gives  a  violet  color  and  then  dis- 
solves the  fibre.  lodin  colors  the  fibres  yellow  to  reddish  brown. 

Carded  silk,  which  has  been  worked  up  from  imperfect 
cocoons,  etc.,  can  usually  be  recognized  under  the  microscope 
by  the  irregular  and  torn  appearance  of  its  external  layer  of  gum. 

The  inner  layers  of  the  cocoon  consist  of  a  yellow  parch- 
ment-like skin,  and  when  examined  under  the  microscope  exhibit 
a  matrix  of  sericin,  in  which  numerous  double  fibres  are 

120 


PHYSICAL  PROPERTIES   OF  SILK  121 

imbedded,  usually  very  much  flattened  in  cross-section  (Fig.  39,  a) . 
These  inner  layers,  of  course,  are  not  capable  of  being  reeled  with 
the  rest  of  the  cocoon,  and  are  used  for  waste  silk.  The  cross- 
sections  of  the  fibres  from  the  middle  portion  of  the  cocoon,  con- 
stituting the  reeled  silk,  are  much  more  rounded  in  form  and  are 
surrounded  with  a  thinner  layer  of  sericin  (see  Fig.  39,  b).  The 
fibres  of  the  outer  part  of  the  cocoon,  also  utilized  for  waste  silk, 
exhibit  a  rather  irregular  cross-section  (see  Fig.  39,  c). 

When  raw  silk  is  examined  under  the  microscope  it  will  be 
seen  that  the  appearance  is  by  no  means  regular,  owing  to  the 
broken  and  torn  surface  of  sericin  which  surrounds  the  fibre 


FIG.  39. — Cross-sections  of  Silk  Fibre. 
a,  from  inner  part  of  cocoon;   b,  from  middle  layers;   c,  from  outer  part;  /,  fibre 
of  fibroin;  s,  layer  of  sericin.     (Micrograph  by  author.) 

(see  Fig.  40).  Frequently  the  two  filaments  of  fibroin  are 
distinctly  separated  from  one  another  for  considerable  distances, 
the  intervening  space  being  filled  in  with  sericin.  Occasionally 
the  layer  of  sericin  is  seen  to  be  entirely  absent,  having  been 
removed  by  breaking  or  rubbing  off.  The  sericin  layer  also 
shows  frequent  traverse  fissures,  which  are  merely  cracks  caused 
by  the  breaking  of  the  sericin  in  the  bending  or  twisting  of  the 
fibre.  Creases  and  folds  in  the  sericin,  as  well  as  irregular 
lumps,  are  also  of  frequent  occurrence.  All  of  these  markings 
are  in  nowise  structural,  and  only  occur  in  the  sericin  layer. 
At  times  the  fibroin  fibre  exhibits  structural  changes  in  places, 
such  as  attenuations;  but  these  only  occur  in  defective  and 
unhealthy  silk,  and  give  rise  to  weak  places.  These  are  caused 
by  the  fibroin  not  being  secreted  by  the  gland  with  sufficient 
rapidity  when  the  fibre  is  being  spun  by  the  worm. 

The  microscopic  appearance  of  the  wild  silks  is  very  different 
from  that  of  the  Bombyx  mori.  The  fibres  are  very  broad  and 
thick,  and  in  cross-section  are  very  flat,  and  often  triangular 
in  outline.  Longitudinally  they  show  very  distinct  striations 


122 


THE  TEXTILE  FIBRES 


and  peculiar  flattened  markings,  usually  running  obliquely 
across  the  fibre,  and  in  which  the  striations  become  more  or 
less  obliterated.  These  cross-markings  are  caused  by  the 
overlapping  of  one  fibre  on  another  before  the  substance  of  the 
fibre  had  completely  hardened,  in  consequence  of  which  these 
places  are  more  or  less  flattened  out  (see  Fig.  41).  The  striated 
appearance  of  wild  silk  is  evidence  that  structurally  the  fibre  is 


FIG.  40. — Appearance  of  Raw  Silk  (X5oo)  under  the  Microscope,  showing  the 
Double  Cocoon  Filament  and  the  Irregular  Shreds  of  Silk-glue.  (Micro- 
graph by  author.) 

composed  of  minute  filaments ;  in  fact  the  latter  may  readily  be 
isolated  by  maceration  in  cold  chromic  acid  (see  Fig.  42) .  Accord- 
ing to  Hohnel,  these  structural  elements  are  only  0.3  to  1.5  y.  in 
diameter;  they  run  parallel  to  each  other  through  the  fibre,  and 
are  rather  more  dense  at  the  outer  portion  of  the  fibre  than  in  the 
inner  part  (see  Fig.  43).  Besides  the  fine  striations  on  the  fibres 
of  wild  silk  caused  by  their  structural  filaments,  there  are  also 
to  be  noticed  a  number  of  irregularly  occurring  coarser  striations. 


PHYSICAL  PROPERTIES   OF  SILK 


123 


These  latter  appear  to  be  due  to  air-canals,  or  spaces  between 
the  filaments  of  the  fibre. 

Hohnel  is  of  the  opinion  that  there  is  really  no  difference 
in  kind  between  the  structure  of  wild  silk  and  that  of  cultivated 
silk;  that  is  to  say,  the  fibroin  fibre  of  the  latter  is  also  composed 
of  structural  filaments,  only  they  fuse  into  one  another  in  a 
more  homogeneous   manner  on 
emerging  from  the  fibroin  glands, 
thus  rendering  it  more  difficult 
to  recognize  them  superficially. 
This  view  is  upheld  somewhat  by 
the  fact  that  a  slight  striated  ap- 
pearance may  be  noticed  when 
the  silk   fibre    is   macerated  in 
chromic  acid  solution.     This  ap- 
parent structure  of  the  silk  fibre, 
however,  may  also   be  due    to 
another  cause.     If  a  plastic  glu- 
tinous  mass    (such    as    melted 
glue,  for  instance)  be  pulled  out 
into  the  form  of  a   thread  and 
allowed    to    harden,  it    will  be 
found  to  exhibit  the  same  stri- 
ated structure  as  the  silk  fibre ;  and  this  structure  will  be  more 
apparent  if  the  thread  is  pulled  out  and  hardened  more  rapidly. 
The  liquid  fibroin  in  the  glands  of  the  worm  is  a  plastic  glutinous 
mass  analogous  to  melted  glue,  and  is  pulled  out  into  the  form  of  a 
thread  by  the  action  of  the  worm  in  winding  its  cocoon ;   hence  it 
would  be  natural  to  expect  a  striated  structure  similar  to  that 
observed  in  the  thread  of  glue.     Thus,  it  is  possible  to  account  sat- 
isfactorily for  the  structure  of  the  silk  fibre  in  a  perfectly  natural 
manner  without  having  recourse  to  a  very  doubtful  organic 
process  in  the  formation  of  the  fibre,  such  as  is  supposed  to  be 
the  case  by  Hohnel. 

2.  Physical  Properties  of  Silk,  fa)  Hygroscopic  Nature. — 
Silk  is  quite  hygroscopic,  and  under  favorable  circumstances 
will  absorb  as  much  as  30  per  cent  of  its  weight  of  moisture 


FIG.  41.— Wild  Silk.  (X25o.) 
A,  view  of  narrow  side;  B,  view  of 
broad  side;  C,  cross-section;  D, 
cross-section  of  double  fibre; 
cr,  cross-marks  on  fibre.  (Micro- 
graph by  author.) 


124 


THE  TEXTILE   FIBRES 


and  still  appear  dry.  It  is  therefore  customary  to  determine 
the  amount  of  moisture  in  each  lot  at  the  time  of  sale.  This 
is  called  conditioning  (see  p.  532),  and  is  usually  carried  out 
in  official  laboratories.*  The  amount  of  "  regain  "  which  is 
legally  permitted  is  n  per  cent;  this  would  be  equivalent  to 
9.91  per  cent  of  moisture  in  the  silk.  Boiled-off  silk  appears 
to  contain  somewhat  less  moisture  than  raw  silk,  the  silk  gum 


FIG.  42. — Tussah  Silk.     (X4oo.)     A,  view  of  broad  side;    C,  cross-mark;    B, 
cross-sections;  E,  torn  end  showing  fibrillae.     (Micrograph  by  author.) 

having  a  greater  attraction,  or  power  of  absorbing  water,  than 
the  fibre  proper.  The  amount  of  moisture  in  boiled-off  silk 
is  usually  regarded  as  about  8.45  per  cent,  which  would  cor- 
respond to  a  regain  of  9.25  per  cent. 

(b)  Electrical  Properties. — Being  a  bad  conductor  of  elec- 
tricity, silk  is  readily  electrified  by  friction,  which  circumstance 
at  times  renders  it  difficult  to  handle  in  the  manufacturing 

*The  Milan  Commission  (1906)  adopted  a  temperature  of  140°  C.  for  the 
conditioning  of  silk,  as  it  is  found  to  be  difficult  to  completely  dry  the  fibre  at 

O/**<  "^*    i 

IIO-I2O     C. 


PHYSICAL  PROPERTIES   OF  SILK 


125 


process.     The  trouble  can  be  overcome  to  a  great  extent  by 
keeping  the  atmosphere  moist. 

(c.)  Lustre. — The  most  striking  physical  property  of  silk, 
perhaps,  is  its  high  lustre.  The  lustre  only  appears  after  the 
silk  has  been  scoured  and  the  silk-gum  removed.  The  lustre 
of  silk  is  affected  more  or  less  by  the  various  operations  of  dye- 
ing and  mordanting,  and  especially  when  the  silk  is  heavily 


FIG.  43.— Cross-section  of  Wild  Silk. 

A,  diagramatic  drawing  of  section;  i,  air-space;  g,  ground  matrix;  /,  fibrillse- 
r,  marginal  layer;  B,  end  of  fibre  of  tussah  silk  swollen  in  sulphuric  acid; 
C,  cross-section  of  fibre  of  tussah  silk  swollen  in  sulphuric  acid.  (After 
Hohnel.) 

weighted.  After  dyeing,  especially  in  the  skein  form,  silk 
usually  undergoes  what  is  termed  a  lustering  operation,  which 
consists  generally  in  stretching  the  hanks  strongly  by  twisting, 
and  simultaneously  steaming  under  pressure  for  a  few  minutes. 
This  process  seems  to  bring  back  to  a  considerable  extent  the 
lustre  of  the  dyed  silk.  Lustering,  or  "  brightening,"  may  also 
be  accomplished  by  steeping  the  skeins  of  silk  in  a  solution  of 


126  THE   TEXTILE  FIBRES 

dilute  acid,  such  as  acetic  or  tartaric,  squeezing,  and  dry- 
ing without  washing.  The  lustre  is  also  considerably  affected 
by  the  method  of  dyeing  and  the  chemicals  employed  in  the 
dye-bath;  it  has  been  found  that  the  addition  of  boiled-off 
liquor  (the  soap  solution  of  sericin  obtained  in  the  degumming 
of  raw  silk)  to  the  dye-bath  has  the  result  of  preserving  the 
lustre  of  the  dyed  silk  better  than  anything  else,  and  in  conse- 
quence boiled-off  liquor  is  nearly  always  employed  as  the  assistant 
in  dyeing  in  preference  to  Glauber's  salt  or  common  salt. 

(d)  Tensile  Strength.— Silk  is  also  distinguished  by  its  great 
strength.     It  is  said  that  its  tensile  strength  is  almost  equal 
to  that  of  an  iron  wire  of  equal  diameter.*     The  silk  fibre  is 
also  very  elastic,  stretching  15  to  20  per  cent  of  its  original 
length  in  the  dry  state  before  breaking.     Degummed  or  boiled 
off  silk  is  somewhat  lower  in  strength  and  elasticity  than  raw 
silk,  the  removal  of  the  silk-gum  apparently  causing  a  decrease 
of  30  per  cent  in  the  tensile  strength  and  45  per  cent  in  the 
elasticity.     The  weighting  of  silk  also  causes  a  decrease  in  its 
strength  and  elasticity. 

The  table  on  page  127  gives  the  diameter,  elasticity,  and  ten- 
sile strength  of  the  cocoon-thread  of  the  chief  varieties  of  silks,  f 

(e)  Density. — The  density  of  silk  in  the  raw  state  is  1.30 
to  1.37,  while  boiled-off  silk  has  a  density  of  1.25. 

(f)  Scoop. — Another  property   of   silk,   and   one   which   is 
peculiar  to  this  fibre,  is  what  is  termed  its  scroop;    this  refers 
to  the  crackling  sound  emitted  when  the  fibre  is  squeezed  or 
pressed.     To   this  property   is  due   the  well-known  rustle   of 
silken  fabrics.     The  scroop  of  silk  does  not  appear  to  be  an 
inherent  property  of  the  fibre  itself,  but  is  acquired  when  the 
silk  is  worked  in  a  bath  of  dilute  acid  (acetic  or  tartaric)  and 
dried  without  washing.     A  satisfactory  explanation  to  account 
for  the  scroop  has  not  yet  been  given;  it  is  probably  due  to  the 
acid  hardening   the   surface   of   the  fibre.     Mercerized   cotton 
can  also  be  given  a  somewhat  similar  scroop  by  such  a  treatment 

*  The  breaking-strain  of  raw  silk  is  equivalent  to  about  64,000  Ibs.  per  sq.  in., 
or  nearly  one-third  that  of  the  best  iron  wire. 
t  Wardle,  Jour.  Soc.  Arts,  vol.  33,  p.  671. 


PHYSICAL  PROPERTIES   OF  SILK 


127 


• 

Diameter, 
Ins. 

Elasticity, 
Ins.  in  One  Ft. 

Tensile 
Strength, 
Drams. 

Size  of 

Name  of  Silk. 

try. 

Cocoon, 
Ins. 

Outer 

Inner 

Outer 

Inner 

Outer 

Inner 

Fibres. 

Fibres. 

Fibres. 

Fibres. 

Fibres. 

Fibres. 

• 

Bombyx  mori  

China 

.00052 

.00071 

i-3 

1.9 

1.6 

2.6 

.1X0.5 

Bombyx  mori  

Italy 

•00053 

.00068 

I  .  2 

1.9 

1.9 

2.6 

.2X0.6 

Bombyx  mori  

Japan 

.00057 

.00069 

.  2 

1.4 

2  .0 

3-1 

.1X0.6 

Bombyx  fortunatus  . 

Bengal 

.000451.00051 

.8 

2-3 

1.6 

2.8 

.2X0.5 

Bombyx  textor  

India 

.00042 

.00047 

.5 

1.9 

i-4 

2.6 

.2X1.5 

Antheraea  mylitta.  .  . 

India 

.00161 

.00172 

•9 

2.7 

6.6 

7-8 

.5X0.8 

Attacus  ricini  

India 

00085 

.00093 

.  7 

2.O 

i  .5 

3.0 

1.5X0.8 

Attacus  cynthia.  .  .  . 

India 

.00083 

.00097 

2.6 

2.9 

2.4 

3-5 

1.8X0.8 

Antheraea  assama.  .  . 

India 

.00128 

.00125 

2.4 

2.9 

2.8 

4-8 

1.8X1.0 

Attacus  selene  

India 

.OOIOO 

.OOI09!      2.O 

2.8 

2.4 

4.0 

3.0X1.2 

Attacus  atlas  

India 

.00102 

.OOIII 

1.9 

2.8 

2.  I 

4-i 

3.5X0.8 

Antheraea  yama-mai 

Japan 

.00088 

.  00096 

2.0 

4.0 

6.8 

7-5 

1.5X0.8 

Cricula  trifenestrata 

India 

.  OOI  2O 

2.0X0.8 

Antheraea  pernyi  .  .  . 

China 

.00118 

.00138 

2  .O 

2.7 

3-2 

5-8 

1.6X0.8 

witji  dilute  acetic  acid.  Wool,  under  certain  conditions  of 
treatment,  in  some  degree  can  also  be  given  this  silk-like  scroop, 
as,  for  instance,  when  it  is  treated  with  chloride  of  lime  solu- 
tions or  with  strong  caustic  alkalies. 

3.  Silk-reeling. — The  silk  fibre,  as  it  appears  in  trade  for 
use  in  the  manufacture  of  textiles,  is  obtained  by  unreeling 
the  cocoon.  After  the  cocoons  have  been  spun  by  the  silk- 
worms they  are  heated  in  an  oven  for  several  hours  at  a  tem- 
perature of  from  60°  to  70°  C.,  for  the  purpose  of  killing  the 
pupa  or  chrysalis  contained  within,  before  the  latter  shall  have 
developed  sufficiently  to  begin  cutting  its  way  through  the 
envelope  and  thus  destroy  the  continuity  of  the  cocoon- thread. 
Another  method  of  operation  is  to  steam  the  cocoons;  this 
requires  only  a  few  minutes  to  kill  the  pupa,  and  is  said  to  be 
preferable  to  the  oven-heating,  as  it  causes  less  damage  to  the 
fibre,  and  at  the  same  time  considerably  softens  the  silk- 
glue,  thus  rendering  the  subsequent  process  easier.  After  the 
killing  of  the  worms  is  accomplished,  the  cocoons  are  sorted 
into  several  grades,  according  to  size,  color,  extent  of  damage, 
etc.,  after  which  they  are  ready  for  reeling.  This  is  entirely  a 


128 


THE  TEXTILE   FIBRES 


mechanical  process  requiring  much  skill.  The  cocoons  are 
soaked  in  warm  water  until  the  silk-glue  is  softened;  the 
operator  seizes  the  loose  ends  of  several  fibres  together  on  a 
small  brush  and  passes  them  through  the  porcelain  guides  of 
a  reel,  where  they  are  twisted  together  to  form  threads  of  suf- 
ficient size  for  weaving.  Two  threads  are  formed  simultaneously 
on  each  reel,  and  are  made  to  cross  and  rub  against  each  other 
to  remove  twists  in  the  fibre  (see  Fig.  44),  and  also  to  rub  the 
softened  silk-glue  coverings  together  in  order  that  the  fibres 


FIG.  44.— Showing  Methods  of  Reeling  the  Silk  Fibre  from  the  Cocoon. 

may  become  firmly  cemented  and  form  a  uniform  thread. 
The  product  so  obtained  is  termed  raw  silk  or  grege;*  floss 
silk,  which  is  used  for  making  spun  silk,|  is  the  term  applied 
to  the  waste  resulting  from  short  and  tangled  fibres  from  the 
exterior  of  the  cocoon,  and  from  those  cocoons  which  have 

"Singles"  is  the  name  applied  to  all  raw  silk  composed  of  a  number  of  silk 
filaments  twisted  together  during  the  reeling  of  the  silk. 

t  Yarns  made  from  spun  silk  differ  considerably  from  reeled  silk  in  being 
fuller,  bulkier,  and  softer;  they  have  less  lustre  than  reeled  yarns,  are  not  so  uni- 
form, and  cannot  be  spun  to  such  fine  counts.  Spun  silk  yarns  are  extensively 
used  for  the  production  of  velvets  and  plushes,  for  striping  and  checking  in 
woolen  and  worsted  fabrics,  for  silk  handkerchiefs,  hosiery,  laces,  etc.  Com- 
bination yarns  are  also  largely  made  by  twisting  a  spun  silk  thread  around  a 
woolen,  worsted,  or  cotton  thread.  Spun  silk  yarns  are  also  extensively  employed 
as  a  warp  with  woolen,  worsted,  or  cotton  filling  for  the  production  of  umbrella 
cloth,  scarfs,  etc. 


PHYSICAL  PROPERTIES  OF  SILK  129 

been  broken  by  the  moth  in  escaping.  Raw  silk  is  classified 
into  two  grades:  (a)  Organzine  silk,  which  is  made  from  the 
best-selected  cocoons,  and  is  chiefly  used  for  wrarps  on  account 
of  its  greater  strength;  and  (b)  Tram  silk,*  which  is  made  from 
the  poorer  quality  cocoons,  and  is  mostly  employed  for  filling. 
Floss  or  waste  silk  cannot  be  reeled,  so  the  cocoon-threads  are 
scoured  in  a  solution  of  soda  and  soap,  and  afterwards  combed 
and  carded  in  special  machines.  There  are  two  ways  in  which 
waste  silk  may  be  degummed  for  spinning:  it  may  either  be 
boiled-off  or  chapped.  The  former  is  usually  adopted  where  all 
the  gum  is  to  be  removed,  and  is  carried  out  by  tying  the  silk 
up  in  bags  and  boiling  in  a  soap  solution.  In  the  second  method 
the  gum  is  loosened  by  a  process  of  fermentation  and  only  a 
portion  of  the  gum  is  removed  according  to  requirements. 
The  process  is  carried  to  such  perfection  that  as  much  as  15 
per  cent  or  as  little  as  2  per  cent  of  the  gum  may  be  removed. 
In  chapping,  the  waste  silk  is  piled  in  a  heap  in  a  damp,  warm 
place,  and  kept  constantly  moist;  the  gum  soon  begins  to  fer- 
ment and  soften;  by  continual  turning  of  the  pile  all  portions 
of  the  heap  are  properly  softened,  but  the  process  takes  several 
days.  Another  process  is  to  place  the  silk  in  cages  and  immerse 
in  water  for  several  days.  The  better  quality  and  longer  fibre 
is  of  waste  silk  worked  up  into  what  is  known  as  florette  silk, 
while  the  shorter  fibres  are  carded  and  spun  into  bourette  silk.f 
Floss  silk  is  also  known  as  chappe  or  echappe  silk. 

According  to  the  composition  and  twist  of  the  threads, 
silk  is  classified  into  the  following: 

i.  Organzine  (warp  or  Orsey  silk);  from  3  to  8  cocoon 
threads  are  lightly  twisted  together  with  a  right-hand  twist, 
so  that  there  are  from  60  to  80  turns  per  cm.,  and  2  to  3  such 
threads  are  twisted  together  left-handed  to  form  double  or 
threefold  organzine. 

*  "Tram"  silk  is  the  union  of  two,  three,  or  more  singles,  only  slightly  twisted 
together,  and  is  known  as  2-thread,  3-thread,  etc.,  tram  according  to  the  number 
of  singles  used  in  the  thread.  Tram,  as  a  rule,  is  used  boiled-off,  and  only  rarely 
in  the  gum,  being  degummed  before  dyeing  in  the  hank.  "Organzine"  silk  is 
the  union  of  a  2-thread  tram  yarn  with  a  large  number  of  turns  per  inch  of  twist. 

t  Silk  wadding  is  produced  from  the  waste  left  after  bourette  spinning. 


130  THE  TEXTILE  FIBRES 

2.  Tram   or    weft   silk;     characterized    by   a   much    lower 
degree  of  twist;    the  individual  threads  consisting  of  3  to  12 
cocoon- threads  undergo  no  preliminary  twist,  and   2  or  3  of 
these  are  united  by  loose  twisting,  so  that  the  thread  is  softer 
and  flatter  than  organzine. 

3.  Marabout  silk;    used    for   making  crepe,  2  to  3  threads 
being   united   without   any   preliminary    twisting,    then   dyed 
without  scouring  and  strongly  twisted;  a  hard  twist  and  stiffness 
are  characteristic  of  this  silk. 

4.  "  Sole    Ondee;"  prepared    by  doubling    a  coarse    and  a 
fine  thread;    it  is  mostly  used  for  making  gauze,  and  .gives  a 
moire  or  watered  appearance. 

5.  Cordonnet;    4  to  8  twisted  threads  are    combined    by  a 
loose  left  twist,  and  3  of  the  threads  thus  formed  are  united  by 
a  right-handed  twist;    this  silk  is  mostly  used  for  selvages, 
braiding,  crocheting,  knitting,  etc. 

6.  Sewing  silk;    made  from    raw  silk    of  3  to  24    cocoon- 
threads,  2,  4,  or  6  of  which  are  united  by  twisting. 

7.  Embroidery  silk;  consists  of  a  number  of  simple  untwisted 
threads  united  by  a  slight  twisting. 

8.  Foil  or  single  silk;   a  raw  silk  thread  formed  by  twisting 
8  to   10  cocoon- threads  and  employed  for  making  gold  and 
silver  tinsel.* 

*  Herzfeld,  Yarns  and  Textile  Fabrics,  p.  89. 


CHAPTER    VIII 

CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK 

i.  Chemical  Constitution. — The  glands  of  the  silkworm 
appear  to  secrete  two  transparent  liquids.  The  one,  fibroin, 
constituting  from  one-half  to  two-thirds  of  the  entire  secretion, 
forms  the  interior  and  larger  portion  of  the  silk  fibre;  the 
other,  sericin,  also  called  silk-glue,  forms  the  outer  coating 
of  the  fibre.  The  latter  substance  is  yellowish  in  color,  and  is 
readily  soluble  in  boiling  water,  hot  soap,  and  alkaline  solu- 
tions. As  soon  as  discharged  into  the  air,  the  fluids  from  the 
spinneret  solidify,  and  coming  into  contact  with  each  other 
at  the  moment  of  discharge  are  firmly  cemented  together  by 
the  sericin. 

The  amount  of  sericin  present  in  raw  silk  is  about  25  per 
cent,  and  this  causes  the  fibre  to  feel  harsh  and  to  be  stiff  and 
coarse.  Before  being  manufactured  into  textiles,  the  raw  silk  is 
subjected  to  several  processes  with  a  view  to  making  it  soft 
and  glossy.  The  first  treatment  is  called  discharging,  stripping, 
or  degumming,  and  has  for  its  purpose  the  removal  of  the  silk- 
glue.*  It  is  really  a  scouring  operation,  the  silk  being  worked 
in  a  soap  solution  at  a  temperature  of  95°  C.  In  this  process 
the  silk  loses  from  20  to  30  per  cent  in  weight,  but  becomes 
soft  and  glossy.  Alkaline  carbonated  are  not  to  be  recommended 
for  silk  scouring,  as  they  are  liable  to  injure  the  fibre,  especially 
at  elevated  temperatures.  Soft  water  should  also  be  employed, 
as  lime  makes  the  fibre  brittle.  After  several  successive 
scourings  the  soap  solution  becomes  heavily  charged  with 
sericin,  and  is  subsequently  utilized  in  the  dye-bath  as  an 
assistant  under  the  name  of  boiled-off  liquor. 

*  Piece-dyed  silk  goods,  like  plain  and  figured  pongees,  satins,  and  similar 
fabrics,  are,  as  a  rule,  woven  with  silk  in  the  gum  state,  the  fabrics  being  after- 
wards boiled-off  or  ungummed.  This,  however,  is  not  possible  with  fancy  colored 
fabrics. 

131 


132 


THE  TEXTILE   FIBRES 


According  to  Mulder,  samples  of  yellow  Italian  silk  analyzed 
as  follows: 

Per  Cent. 

Silk  fibre 53  35 

Matter  soluble  in  water 28 . 86 

alcohol 1.48 

ether o.oi 

* '         ' '         acetic  acid 16 . 30 

He  gives  the  chemical  composition  of  the  silk  fibre  as  follows : 

Per  Cent. 

Fibroin 53-37 

Gelatin 20 . 66 

Albumin 24 . 43 

Wax i .  39 

Coloring  matter o .  05 

Resinous  and  fatty  matter o .  10 

According  to  Richardson,  mulberry  silk  has  the  following 
composition:* 

Per  Cent. 

Water .  .  1 2 .  50 

Fats o.  14 

Resins o .  56 

Sericin 22 . 58 

Fibroin 63 . 10 

Mineral  matter 1.12 

*  Suzuki,  Yoshimura,  and  Inouye  (Jour.  Coll.  Agric.  Imp.   Univ.  Tokio,  1909, 
p.  59)  give  the  following  analyses  of  samples  of  various  Japanese  raw  silks: 


Bombyx 
Mori, 
Per  Cent. 

Sakusan, 
Per  Cent. 

Yama-mai, 
Per  Cent. 

Kuri-wata, 
Per  Cent. 

Moisture 

12   QO 

13  16 

1  1    20 

• 
II    71 

Dry  substance  

87.10 

86.84 

88.71 

88.29 

100  parts  dry  fibre  yielded: 
Ash  
Soluble  in  boiling  HC1 

0.63 
00    14 

2.92 

92    21 

4-73 
07   o? 

3-85 

88  34 

Insoluble  in  boiling  HC1 

o  86 

7    7O 

2    03 

ii  66 

Total  nitrogen  

18  98 

18  87 

17-73 

16.  73 

Nitrogen  soluble  in  HC1    

18  86 

16  30 

17   26 

ic    77 

Nitrogen  insoluble  in  HC1  

O.  12 

2.48 

0.47 

0.96 

100  parts  of  the  total  nitrogen  showed: 
Nitrogen  soluble  in  boiling  HC1  .... 
Ammonia  nitrogen  

99-34 
4-  "?7 

86.87 
2.52 

97-34 
3.85 

94.26 
4.08 

Nitrogen  ppt.  by  phosphotungstic 
acid  

1.78 

13  .  ii 

10  .44 

15.54 

CHEMICAL  NATURE  AND   PROPERTIES  OF  SILK       133 

Analyses  of  samples  of  mulberry  silk  are  given  by  H.  Silber- 
mann  *  as  follows: 


White. 

Yellow. 

Cocoons. 

Raw. 

Cocoons. 

Raw. 

Fibroin  

73-59 
0.09 
22.28 
3.02 
i.  60 

76.  20 
0.09 

22.  OI 
1.36 
0.30 

70.02 
o.  16 
24.29 
3-46 
1.92 

72.35 
0.16 

23-13 
2-75 
i.  60 

Ash  of  fibroin  

Sericin  
Wax  and  fat  
Salts  

Silbermann  also  gives  a  table  showing  the  difference  in  the 
elementary  composition  between  mulberry  silk  and  tussah  silk: 


Mulberry  Silk. 

Tussah  Silk. 

Cocoon 
Threads. 

Fibroin. 

Cocoon 
Threads. 

Fibroin. 

Carbon 

36.77 
6.21 

17-57 
28.25 

I  .  20 

47-47 
6-37 
17.86 
28.01 
o.  29 

46.96 
6.26 
17.60 
26.39 
2.85 

48.50 
6.34 
18-37 
26  .  39 
0.40 

Hydrogen  
Nitrogen 

Oxygen 

Ash  

The  amount  of  ash  in  boiied-off  silk  will  vary  somewhat 
according  to  the  origin  of  the  silk,  but  will  average  about  0.50 
per  cent.  In  raw  silk  the  average  amount  of  ash  will  be  about 
i  per  cent.  In  yama-mai  silk  the  ash  may  reach  as  high  as  8 
per  cent.  Allen  f  states  that  the  greater  part  of  the  mineral 
matters  of  raw  silk  are  simply  adherent  to  the  fibre,  and  are 
removed  together  with  the  sericin  by  prolonged  boiling  with 
soap  solution;  the  residual  fibroin  retains  only  about  0.6  per 
cent  of  mineral  matter. 

2.  Fibroin. — This  substance  is  a  proteid  somewhat  analogous 
to  that  contained  in  wool,  and,  like  the  latter,  is  no  doubt 


*  Die  Seide,  vol.  2,  p.  210. 

f  Commercial  Organic  Analysis,  vol.  4,  p.  507. 


134  THE  TEXTILE  FIBRES 

an    amino-acid.     Mulder    gives    the     analysis    of    fibroin     as 
follows  : 

Per  Cent. 
Carbon  .......................................  48  .  80 

Hydrogen  .....................................     6  .  23 

Oxygen  ................................  .  ......    25  .  oo 

Nitrogen  ......................................    19.  oo 

Vignon    analyzed    samples    of    highly    purified     silk,*    and 
gives  the  following  figures:! 

Per  Cent. 
Carbon  ........................................   48  .  3 

Hydrogen  .......  .  ....................  >  .........     6.5 

Nitrogen  .......................................   19.2 

Oxygen  ........................................    26.0 

Richardson   suggests   the   following   structural   formula   for 
fibroin,  allowing  x  to  represent  a  hydrocarbon  residue  : 

NH—  CO, 

x/  V 

XCO—  NHX 

The  decomposition  of  fibroin  by  saponification  with  potash 
would  then  be 


STH—  CO  NH 


/N 


*C  +2KOH  =  2< 

XCO—  NHX  XCO.OK 


According  to  Allen,  {  raw  commercial  silk  from  the  mul- 
berry silkworm  is  generally  regarded  as  containing  n  per  cent 

*  Vignon  prepares  pure  fibroin  in  the  following  manner:  A  lo-gram  skein 
of  raw  white  silk  is  boiled  for  thirty  minutes  in  a  solution  of  15  grams  of  neutral 
soap  in  1500  c.c.  water;  rinse  in  hot,  then  in  tepid  water;  squeeze  and  repeat  the 
treatment  in  a  fresh  soap-bath;  rinse  with  water,  then  with  dilute  hydrochloric 
acid,  again  with  water;  finally,  wash  twice  with  90  per  cent  alcohol.  The  fibroin 
thus  obtained  leaves  only  o.oi  per  cent  of  ash  on  ignition.  (CompL  rend.,  vol. 
115,  pp.  17,  613.) 

t  A  mean  of  analyses  by  a  number  of  well-known  investigators  on  the  com- 
position of  fibroin  is  as  follows: 

Per  Cent. 

Carbon  ......  .................................  48  .  53 

Hydrogen  .....................................     6  .  43 

Nitrogen  ......................................   18  .  33 

Oxygen  .......................................   26.67 

}  Commercial  Organic  Analysis,  vol.  4,  p.  506. 


CHEMICAL   NATURE  AND  PROPERTIES  OF  SILK       135 


of  moisture,  66  per  cent  of  fibroin,  22  per  cent  of  sericin,  and 
i  per  cent  of  mineral  and  coloring  matters. 

The  proportion  of  fibroin  in  raw  silk  has  been  variously 
stated  by  different  observers,  and  appears  to  differ  with  the 
method  employed  for  its  determination.  The  figure  given  by 
Mulder  (see  above)  of  53.35  per  cent  was  obtained  by  boiling 
the  raw  silk  with  acetic  acid.  By  the  action  of  a  5  per  cent 
solution  of  cold  caustic  soda,  Stadeler  obtained  42  to  50  per 
cent  of  fibroin.  Cramer  obtained  66  per  cent  by  heating  raw 
silk  in  water  at  133°  C.  under  pressure.  Francezon  reports 
75  per  cent  of  fibroin  by  twice  boiling  the  silk  in  a  solution  of 
soap  and  then  treating  with  acetic  acid.  Vignon,  by  carefully 
purifying  the  fibroin  by  suitable  treatment,  obtained  75  per 
cent.* 

In  the  Report  of  the  Milan  Commission  on  Silk  (1906) 
it  was  concluded  that  very  great  differences  existed  in  the  propor- 
tion of  fibroin  given  by  silks  from  the  same  races  of  Bombyx  mori, 
depending  on  conditions  of  food,  culture,  etc.  Variations 
in  the  amount  of  fibroin  from  73  to 84  per  cent  have  been  recorded, 
and  hence  it  is  impossible  to  base  an  estimate  of  the  purity 
of  silk  upon  the  results  of  such  a  determination.  Owing  to 
the  fact  that  the  amount  of  substances  soluble  in  a  soap  solu- 
tion varies  from  16  to  27  per  cent,  it  is  obviously  possible  to 
add  to  this  amount  by  artificial  means.  The  permissible 
limits  of  impurities  were  determined  by  the  commission  by 
analyses  of  a  large  number  of  samples  of  known  purity.  From 
these  analyses  the  following  tables  were  prepared: 


Minimum. 
Per  Cent. 

Maximum. 
Per  Cent. 

Mean. 
Per  Cent. 

Substances  soluble  in  3  per  cent  soap  solution  . 
In  distilled  water  at  5o°-55°  C  

21.449 
O  447 

25-9I3 
I   053 

22.865 
o  617 

In  ether 

O    IO4 

O   451 

O    27? 

Ash  

o  726 

O.QO3 

o.8<;<; 

*  According  to  Fischer  and  Skita  (Zeitschr.  physiol.  Chem.,  vol.  33,  p.  171, 
and  vol.  35,  p.  224),  even  technically  purified  silk  still  contains  about  5  per 
cent  of  silk-glue. 


136  THE  TEXTILE   FIBRES 

Unlike  keratin,  the  proteid  of  wool,  fibroin  contains  no 
sulphur,  and  is  much  more  constant  in  its  composition.  The 
empirical  formula  for  fibroin  as  given  by  Mulder  is  CisH^sNsOe. 
Mills  and  Takamine  give  the  formula  as  C24H?8Ns08,  while 
Schlitzenberger  gives  C7iHio?N24025.  Cramer  arrives  at  the 
same  formula  as  Mulder,  while  Richardson*  gives  CooH^NisC^. 
Vignon's  formula  for  specially  purified  fibroin  is  C22H47NioOi2.t 

The  presence  of  the  amino-group  in  fibroin  has  been  shown, 
as  in  the  ^  case  of  wool  (see  page  64),  by  diazotizing  the  fibre 
with  an  acid  solution  of  sodium  nitrite,  then  washing  and  treat- 
ing with  solutions  of  various  developers,  such  as  phenol,  resor- 
cinol,  alpha-  and  beta-naphthols,  etc.,  whereby  the  fibre  becomes 
dyed  in  different  colors. 

From  its  action  towards  alcoholic  potash  Richardson  con- 
cludes that  silk  fibroin  is  probably  an  amino-anhydride  rather 
than  an  amino-acid.  When  boiled  for  a  long  period  with  dilute 
sulphuric  acid,  fibroin  is  dissolved  to  a  yellowish  brown  liquid, 
leaving  as  a  residue  only  a  small  amount  of  what  is  apparently 
a  fatty  acid.  From  this  decomposition  product  WeylJ  suc- 
ceeded in  isolating  5.2  per  cent  of  ty rosin,  7.5  per  cent  of  glycosin 
and  1 5  per  cent  of  a  crystalline  compound  which  was  apparently 
alpha-alanin.  Toward  Millon's  and  Adamkiewitz's  reagents 
fibroin  gives  the  usual  reaction  of  proteids,  and  it  also  gives 
the  biuret  test.§  According  to  Richardson,  silk  fibroin  will 

*  Jour.  Soc.  Chem.  Ind.,  vol.  12,  p.  426. 

t  Silbermann  found  that  fibroin  heated  with  a  solution  of  barium  hydrate 
under  pressure  was  decomposed  with  the  formation  of  oxalic,  carbonic,  and  acetic 
acids,  together  with  an  amino-body  approximating  the  formula  CesHniN^C^. 
The  latter  compound  is  said  to  undergo  further  decomposition  with  the  formation 
of  tyrosin,  glycocin,  alanin,  amino-butyric  acid,  and  an  amino-acid  of  the  acrylic 
series.  Fischer  and  Skita  (Zeitschr.f.  physiol.  Chem.,  vol.  33,  p.  177)  have  shown 
that  in  all  probability  amino-valerianic  acid,  C3H7-CH(NH2)-COOH,  occurs  in 
fibroin.  Silk  fibroin,  however,  appears  to  differ  from  other  albumins  in  not  con- 
taining aspartic  acid,  COOH-CH2-CH(NH2VCO-OH.  Glutaminic  acid, 
COOH-CH2-CH2-CH(NH2)-COOH,  also  appears  to  be  present  in  fibroin,  though 
Fischer  doubts  this. 

\Berichte,  vol.  21,  p.  1529. 

§  Millon's  reagent  consists  of  a  solution  of  mercurous  nitrate  containing  nitrous 
acid  in  solution.  It  is  prepared  by  treating  i  c.c.  of  mercury  with  10  c.c.  of  nitric 
acid  (sp.gr.  1.4),  heating  gently  until  complete  solution  is  effected,  then  diluting 


CHEMICAL  NATURE  AND   PROPERTIES  OF  SILK       137 


absorb  30  per  cent  of  iodin  when  treated  with  Hiibl's  reagent. 
Attempts  have  been  made  to  acetylize  fibroin,  but  without 
success.* 

The  following  table  gives  the  products  of  hydrolysis  obtained 
from  various  kinds  of  silk: 


Bomby 

a  Mori. 

Raw 

Raw 

Raw 

Raw 

Fibroin. 

Sericin. 

Sakusan. 

Yamamai. 

Kuriwata. 

Tussah. 

Glvcocoll 

36  o 

O    I—  O    2 

c    7 

6  3 

7  •  7 

•2S     J2 

Alanin  

21  .'O 

5.0 

4.8 

7-  2 

15.3 

23.4 

Leucin  .    .      .        

I  .  t; 

I  .  2 

1  .3 

7  -CK 

1.76 

Prolin 

O    3 

4  ° 

3  68 

Glutaminic  acid 

o  6 

? 

6  16 

Asparaginic  acid 

I    O 

I    O 

O    2 

Tyrosin 

12    O 

tr   o 

I   4 

2    O 

c    tr 

4  2 

Histidin 

2    7 

i  6 

I    OI 

Arginin  
Ammonia      

I  .0 
I    O^ 

4.0 
1.87 

3-i 
o  6 

3-8 
o  8 

1.74 

o  8 

5-24 
i   16 

Fibroin  is  insoluble  in  ammonia  and  solutions  of  the  alka- 
line carbonates;   neither  is  it  dissolved  by  a  i  per  cent  solution 

the  solution  with  twice  its  volume  of  cold  water.  When  a  solution  of  a  proteid 
is  treated  with  this  reagent,  a  white  precipitate  is  first  formed,  which  turns  brick- 
red  on  boiling;  a  solid  proteid  becomes  red  when  boiled  with  the  reagent.  Adam- 
kiewitz's  test  is  to  dissolve  the  proteid  in  glacial  acetic  acid,  and  then  add  con- 
centrated sulphuric  acid  to  the  solution,  when  a  fine  violet  color  will  be  produced, 
and  the  liquid  will  exhibit  a  faint  fluorescence.  The  biuret  test  is  to  add  a  few 
drops  of  a  dilute  solution  of  copper  sulphate  to  the  solution  of  proteid;  then  on 
adding  an  excess  of  caustic  soda  solution  the  precipitate  which  at  first  formed  will 
be  dissolved  with  the  production  of  a  fine  violet  coloration. 

*  Cohnheim,  in  his  tables  of  the  percentage  composition  of  various  albumins, 
gives  the  following  for  the  fibroin  of  silk: 

Per  Cent. 

Glycocoll 36 

Alanin 21 

Leucin 1.5 

Phenylalanin 1.5 

a-Pyrrolidin-carboxylic  acid 0.3 

Serin 1.6 

Tyrosin 10 

Arginin i 

The  occurrence  of   the   following  compounds  in  indeterminate  amounts  is 
also  given:   Lysin,  histidin,  tryptophane,  and  ammo- valerianic  acid. 


138  THE  TEXTILE  FIBRES 

of  caustic  soda,  but  stronger  solutions  affect  it,  especially  if 
hot.  From  its  solution  in  caustic  soda  fibroin  may  be  repre- 
cipitated  by  dilution  with  water.  Fibroin  is  also  soluble  in 
hot  glacial  acetic  acid,  and  in  strong  hydrochloric,  sulphuric, 
nitric,  and  phosphoric  acids.  Alkaline  solutions  of  the  hydroxides 
of  such  metals  as  nickel,  zinc,  and  copper  also  dissolve  fibroin. 

If  silk  fibroin  is  dissolved  in  cold  concentrated  hydrochloric 
acid,  and  the  solution  be  allowed  to  stand  sixteen  hours  at  the 
ordinary  temperature  with  three  times  its  volume  of  hydro- 
chloric acid  (sp.gr.  1.19),  it  will  no  longer  be  precipitated  by 
the  addition  of  alcohol.  The  fibroin  appears  to  have  suffered 
hydrolysis,  being  converted  into  a  body  similar  to  peptone. 
This  substance  may  be  separated  out  by  steaming  the  above 
solution  under  diminished  pressure.*  If  its  aqueous  solution 
be  neutralized  with  ammonia  and  some  trypsin  ferment  be 
added,  tyrosin  will  begin  to  crystallize  out  in  a  few  hours. 

3.  Sericin.  —  According  to  the  analysis  of  Richardson,  ser- 
icin  has  the  following  composition: 

Per  Cent. 
Carbon  .......................................  48  .  80 

Hydrogen  .....................................     6  .  23 

Oxygen  .....  •  ...................................    25.97 

Nitrogen  ......................................    19  .  oo 


and  its  formula  is  given  as  CieH^sNsOg.  It  is  considered  by 
some  as  an  alteration  product  of  fibroin;  strong  hydrochloric 
acid  is  said  to  convert  the  latter  into  sericin;  the  conversion 
is  supposed  to  take  place  by  assimilation  of  water  and  oxygen. 


Fibroin.  Sericin 


*  Fischer  and  Abderhalden  (Berichte,  1906,  p.  752)  have  succeeded  in  isolating 
from  the  hydrochloric  acid  solution  of  silk  fibroin  a  dipeptide  in  the  form  of 
methyl-diketopiperazine,  having  the  formula 


The  yield  is  about  1  2  per  cent,  and  the  product  is  identical  with  that  obtained 
synthetically  from  glycocoll  and  J-alanin. 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK      139 

Sericin  may  be  obtained  in  a  pure  condition  by  first  boiling  a 
sample  of  raw  silk  in  water  for  several  hours,  after  which  the 
sericin  is  precipitated  by  lead  acetate.  Pure  sericin  may 
also  be  prepared  by  precipitating  crude  sericin  solution  with 
i  per  cent  acetic  acid,  washing  the  separated  sericin  by  repeated 
decantation  with  water,  then  treating  with  cold  and  afterwards 
with  boiling  alcohol,  and  finally  extracting  with  ether.  Pure 
sericin  contains 

Per  Cent. 
Carbon  .......................................  45  -  °o 

Hydrogen  .....................................     6.32 

Nitrogen  ......................................    17  •  U 

Oxygen  .......................................   31-54 

It  is  easily  soluble  in  water,  in  concentrated  hydrochloric 
acid,  and  in  potassium  carbonate;  sodium  carbonate  only 
causes  a  swelling. 

On  treatment  with  dilute  sulphuric  acid,  sericin  yields  a 
small  quantity  of  leucin  and  tyrosin,  but  no  trace  of  glycocoll, 
the  principal  product  formed  being  a  crystalline  body  called 


serin,    which     appears    to    have    the    formula    C2H4\  , 

XCOOH 

and  from  its  chemical  reactions  is  evidently  analogous  to  gly- 
cocin,  probably  being  amino-glyceric  acid. 

Sericin  is  soluble  in  hot  water,  hot  soap  solutions,  and  dilute 
caustic  alkalies.  The  aqueous  solution  is  precipitated  by  alcohol, 
tannin,  basic  lead  acetate,  stannous  chloride,  bromin,  and 
iodin,  and  by  potassium  ferrocyanide  in  the  presence  of  acetic 
acid.  By  treatment  with  formaldehyde,  it  is  claimed  that 
sericin  is  rendered  insoluble  in  both  hot  water  and  soap  solutions  ; 
consequently,  raw  silk  may  be  treated  with  this  reagent  for  use 
in  certain  applications  where  it  may  be  desired  to  retain  as  far 
as  possible  the  coating  of  silk-glue. 

Mulder  gives  the  formula  of  CisH^NsOs  to  sericin,  and  the 
following  composition: 

Per  Cent. 
Carbon  .......................................  42.60 

Hydrogen  .....................................     5  .  90 

Oxygen  .......................................   35.0 

Nitrogen  ......................................   16  .  50 


140  THE   TEXTILE  FIBRES 

According  to  Bolley,  the  composition  of  sericin  is 


Carbon  

Per  Cent. 

A  A     T.2 

Hydrogen 

6  18 

Oxygen 

-2  T      2O 

Nitrogen  .  . 

.    i8.?o 

According  to  the  tables  of  Cohnheim,  the  percentages  of 
known  constituents  in  silk-glue  are  as  follows: 

Per  Cent. 

Glycocoll 0.1-0.2 

Alanin 5 

Leucin Not  determined 

Serin 6.6 

Tyrosin 5 

Lysin , Not  determined 

Arginin 4 

Ammonia 1.87 

Vignon,*  by  observing  the  action  of  solutions  of  sericin  and 
fibroin  on  polarized  light,  found  that  both  of  these  constituents 
of  silk  were  laevogyrate,  and  their  rotatory  powers  were  about 
equal,  approximating  to  40°.  This  is  in  keeping  with  observa- 
tions made  on  other  albuminoids. 

4.  Coloring  Matter. — According  to  Dubois,f  the  yellow 
coloring  matter  of  silk  is  similar  to  carotin.  J  He  obtained 
five  different  bodies  from  the  natural  coloring  matter  of  silk, 
as  follows:  (i)  A  golden-yellow  coloring  matter,  soluble  in 
potassium  carbonate  and  precipitated  by  acetic  acid;  (2) 
crystals  which  appear  yellowish  red  by  transmitted  light  and 
brown  by  reflected  light;  (3)  a  lemon-colored  amorphous  body, 
the  alcoholic  solution  of  which  on  evaporation  gave  granular 
masses;  (4)  yellow  octahedral  crystals  resembling  sulphur; 

*  Compt.  rend.,  vol.  103,  p.  802. 

f  Ibid.,  vol.  iii,  p.  482. 

JLevrat  and  Conte  (Jour.  Soc.  Chem.  Ind.,  vol.  2,  p.  172)  have  shown  that 
the  color  of  natural  silk  is  due  to  the  coloring  matter  present  in  the  leaves  on 
which  the  silkworms  feed;  chlorophyl  being  the  coloring  matter  in  the  case  of 
green  silks,  while  yellow  silks  contain  the  yellow  coloring  matter  of  the  mulberry 
leaves.  These  investigators  made  experiments  by  feeding  silkworms  with  leaves 
stained  with  various  artificial  dyes,  and  it  was  found  that  the  silk  produced  was 
more  or  less  colored.  The  silk  from  the  Atlacus  orizaba  gave  a  more  pronounced 
color  than  that  from  the  ordinary  silkworm. 


CHEMICAL  NATURE  AND   PROPERTIES  OF  SILK       141 

(5)    a   dark   bluish  green   pigment   in   minute   quantities   and 
probably  crystalline. 

5.  Chemical   Reactions. — In  its   general  chemical  behavior 
silk  is  quite  similar  to  wool. 

(a)  Heat. — It   will   stand   a   higher   temperature,   however, 
than  the  wool  fibre,  without  receiving  injury;  it  can  be  heated, 
for   instance,    to    110°   C.    without   danger   of   decomposition; 
at  170°  C.,  however,  it  is  rapidly  disintegrated.     On  burning 
it  liberates  an  empyreumatic  odor  which  is  not  as  disagree- 
able as  that  obtained  from  burning  wool. 

(b)  Action  of  Acids. — Silk  readily  absorbs  dilute  acids  from 
solutions,  and  in  so  doing  increases  in  lustre  and  acquires  the 
scroop  of  which   mention  has  previously  been  made.     Unlike 
wool,  it  has  a  strong  affinity  for  tannic  acid,*  which  fact  is 
utilized   for  both  weighting  and  mordanting  the  fibre.     Con- 
centrated sulphuric  and  hydrochloric  acids  dissolve  silk;    nitric 
acidj  colors  silk  yellow,  as  in  the  case  with  wool,  probably  due 

*  The  reaction  between  silk  and  tannic  acid  is  different  from  that  with  other 
textile  fibres.  Heermann  (Farb.  Zeit.,  1908,  p.  4)  points  out  that  vegetable 
fibres  absorb  only  small  amounts  of  tannic  acid,  a  state  of  equilibrium  being 
produced  which  depends  on  the  relative  amounts  of  water,  tannic  acid,  and  fibre. 
The  tannic  acid  absorbed  by  vegetable  fibres  is  also  readily  removed  by  cold 
water  (see  Knecht  and  Kershaw,  Jour.  Soc.  Chem.  Ind.,  1892,  p.  129;  also  Geor- 
gievics,  Mitt,  des  tech.  Gewerbe  Museums  in  Wien,  1898,  p.  362).  Wool  absorbs 
but  little  tannic  from  cold  solutions,  and  when  treated  with  hot  solutions  the 
fibre  becomes  harsh.  The  silk  fibre,  however,  behaves  somewhat  like  hide 
in  that  it  absorbs  a  large  amount  of  tannic  acid  from  cold  solutions,  and  as  much 
as  25  per  cent  of  its  weight  from  a  hot  solution.  Furthermore,  the  tannin 
absorbed  by  silk  is  not  readily  removed  by  treatment  with  water.  Heermann 
experimented  on  the  absorption  of  various  tannins  by  silk,  the  following  tannins 
being  employed:  Gambier,  gambiei  substitute,  Aleppo  gall  extract,  sumac 
extract,  and  divi-divi  extract;  the  samples  of  silk  used  for  the  purpose  being  (i) 
pure  silk  which  had  been  degummed,  (2)  silk  dyed  with  Prussian  blue,  and  (3) 
silk  mordanted  with  tin  chloride  and  sodium  phosphate.  The  following  con- 
clusions were  deduced:  Most  tannin  is  absorbed  by  all  three  samples  of  silk 
from  the  gambier  extract;  pure  silk  absorbs  almost  as  much  from  gall  extract 
and  from  sumac  extract,  but  the  prepared  samples  of  silk  showed  only  a  slight 
absorption  of  these  two  tannins.  Divi-divi  comes  next  to  gambier  in  amount 
of  absorption.  Gambier  substitute  is  peculiar,  as  tannin  is  absorbed  from  it 
only  when  the  solutions  are  concentrated. 

fVignon  and  Sisley  (Compt.  rend.,  1891)  found  that  the  purified  fibroin  of 
silk  when  treated  with  nitrous  nitric  acid  increased  2  per  cent  in  weight. 


142  THE  TEXTILE  FIBRES 

to  the  formation  of  xanthoproteic  acid.  This  color  can  be 
removed  by  treatment  with  a  boiling  solution  of  stannous 
chloride.  The  action  of  nitric  acid  on  silk  is  rather  a  peculiar 
one.  When  treated  for  one  minute  with  nitric  acid  of  sp.gr. 
1.33  at  a  temperature  of  45°  C.,  the  silk  acquires  a  yellow  color 
which  cannot  be  washed  out  and  is  also  fast  to  light.  Pure 
nitric  acid  free  from  nitrous  compounds,  however,  does  not 
give  this  color.  On  treating  the  yellow  nitro-silk  with  an 
alkali,  the  color  is  considerably  deepened.  With  strong  sul- 
phuric acid  nitro-silk  swells  up  and  gives  a  gelatinous  mass 
resembling  egg  albumin.  The  solubility  of  silk  in  strong 
hydrochloric  acid  is  very  rapid,  a  minute  or  two  sufficing  for 
complete  solution.  Under  such  conditions  wool  and  cotton 
fibres  are  but  slightly  affected,  hence  such  a  treatment  may  be 
used  for  the  separation  of  silk  from  wool  or  cotton  for  the  pur- 
pose of  analysis.  Though  silk  is  soluble  in  concentrated  acids 
if  their  action  is  continued  for  any  length  of  time,  it  appears 
that  if  silk  be  treated  with  concentrated  sulphuric  acid  for 
only  a  few  minutes,  then  rinsed  and  neutralized,  the  fibre  will 
contract  from  30  to  50  per  cent  in  length  without  otherwise 
suffering  serious  injury  beyond  a  considerable  loss  in  lustre. 
This  action  of  concentrated  acids  on  silk  has  been  utilized  for 
the  creping  of  silk  fabrics,  the  acid  being  allowed  to  act  only 
on  certain  parts  of  the  material.  It  appears  that  tussah  silk 
is  not  affected  by  the  acid  to  the  same  degree  as  ordinary  silk, 
and  hence  creping  may  be  accomplished  by  mixing  tussah  with 
ordinary  silk,  and  treating  the  en  tire  fabric  with  concentrated  acid. 

Hydrofluosilicic  acid  and  hydrofluoric  acid  in  the  cold  and  in 
5  per  cent  solutions  do  not  appear  to  exert  any  injurious  action 
on  the  silk  fibre;  these  acids,  however,  remove  all  inorganic 
weighting  materials,  and  their  use  has  been  suggested  for  the 
restoring  of  excessively  weighted  silks  to  their  normal  condi- 
tion, so  that  they  may  be  less  harsh  and  brittle. 

According  to  Farrell,*  when  silk  is  treated  with  hydro- 
chloric acid  of  a  density  of  29°  Tw.  it  shrinks  about  one-third 
without  any  appreciable  deterioration  in  the  strength  of  the 

*  Jour.  Soc.  Dyers'  6*  CoL,  1905,  p.  70. 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK       143 

fibre.  With  solutions  of  acid  below  29°  Tw.  no  contraction 
occurs,  while  with  solutions  above  30°  Tw.  complete  disintegra- 
tion of  the  fibre  results.  In  the  production  of  crepon  effects 
by  this  method,  the  fabric  is  printed  with  a  wax  resist,  and  is 
then  immersed  in  the  hydrochloric  acid;  the  contraction  is 
complete  in  one  to  two  minutes,  after  which  the  fabric  is  well 
washed  in  water.  Nitric  acid  and  ortho-phosphoric  acid 
may  also  be  employed  for  the  creping  of  silk  fabrics.*  According 
to  a  French  patent  a  similar  effect  may  be  obtained  by  treating 
silk  with  a  solution  of  zinc  chloride  of  from  32°  to  y6°Tw.t 

(c)  Action  of  Alkalies. — Silk  is  not  as  sensitive  to  dilute 
alkalies  as  wool,  though  the  lustre  of  the  fibre  is  somewhat 
diminished.!  When  treated  with  strong  hot  caustic  alkalies 
the  silk  fibre  dissolves.  Ammonia  and  soaps  have  no  effect 
on  silk  beyond  dissolving  the  silk-glue  or  sericin;  though  on 
long-continued  boiling  in  soap,  the  fibroin  is  also  attacked. 
Borax  has  no  injurious  action  on  silk,  but  neither  has  it  any 
special  solvent  action  on  silk-glue,  hence  it  is  not  serviceable 
as  a  stripping  agent.  If  raw  silk  is  steeped  in  lime-water,  the 
fibre  will  swell  to  some  extent  and  the  silk-glue  will  become 
somewhat  softened.  If  the  action  of  the  lime-water  is  con- 
tinued, however,  the  silk  will  become  brittle. 

(d;  Action  of  Metallic  Salts,  etc.— Towards  the  ordinary 
metallic  salts  used  as  mordants  silk  exhibits  quite  an  affinity; 
in  fact,  to  such  an  extent  can  it  absorb  and  fix  certain  metallic 
salts  that  silk  material  is  frequently  heavily  mordanted  with  such 
salts  for  the  purpose  of  unscrupulously  increasing  its  weight. 

The  tensile  strength  of  weighted  silk  is  much  less  than  that 
of  the  pure  silk;  and  furthermore,  the  weighting  materials 
cause  a  rather  rapid  deterioration  of  the  fibre.  Strehlenert  § 
has  shown  that  the  strength  of  black  dyed  silk  weighed  to  140 
per  cent  was  less  than  one-sixth  that  of  the  pure  raw  silk. 
White  and  colored  silks  are  usually  weighted  with  tin  phosphate 

*  See  C.  and  P.  Depoully  Jour.  Soc.  Dyers'  &•  Col.,  1896,  p.  8. 
f  Jour.  Soc.  Dyers'  &  Col.,  1899,  p.  214. 

t  It  is  said  that  when  mixed  with  glucose  or  glycerin  caustic  soda  does  not 
dissolve  the  silk  fibre  to  any  extent,  but  only  removes  the  gum. 
§  Chem.  Zeit.,  1901,  p.  400. 


144  THE  TEXTILE  FIBRES 

and  silicate,  and  this  causes  the  fibre  gradually  to  become 
brittle  and  to  disintegrate.  Reddish  spots  frequently  develop 
on  such  weighted  silk,  probably  resulting  from  the  action  of 
salt  contained  in  the  perspiration  from  the  workman  handling  the 
material.  By  treating  tin  weighted  silk  with  preparations 
containing  ammonium  sulphocyanide,  glycerin,  and  tannin, 
the  rapid  deterioration  of  the  silk  may  be  largely  prevented. 
Sunlight  seems  to  accelerate  the  destructive  action  of  tin 
weighting,  though  according  to  Silbermann*  this  effect  is  much 
reduced  if  stannous  salts  are  absent.  In  this  connection  he 
recommends  the  following  test  to  detect  the  presence  of  the 
stannous  compound  :f  The  sample  of  silk  is  heated  with  an 
acidified  solution  of  mercuric  chloride;  if  tin  in  the  stannous 
condition  is  present,  mercurous  chloride  will  be  deposited  on 
the  fibre  and  will  yield  a  dark  gray  sulphide  when  treated  with 
hydrogen  sulphide.  Silbermann  also  concludes  that  the  presence 
of  ferrous  salts  in  the  iron  mordants  used  for  black  dyed  silk 
has  a  similar  destructive  action  on  the  fibre. 

Treatment  of  weighted  silk  (tin-silico-phosphate  method) 
with  thiourea  and  with  hydrosulphite-formaldehyde  com- 
pounds also  decreases  the  tendering  action  of  the  weighting 
material,  and  such  processes  are  now  in  commercial  use. 

Solutions  of  sodium  chloride  appear  to  have  a  peculiar 
action  on  the  silk  fibre,  especially  in  the  presence  of  weighting 
materials.  According  to  the  researches  of  Sisley,  solutions 
of  common  salt  acting  on  weighted  silk  in  the  presence  of  air 
and  moisture  cause  a  complete  destruction  of  the  fibre  in 
twelve  months,  if  charged  with  but  0.5  per  cent  of  salt;  i  per 
cent  of  salt  causes  a  very  pronounced  tendering  of  the  fibre 
in  two  months,  while  2  to  5  per  cent  of  salt  causes  a  distinct 

*  Zeit.  Farb.  u.  Textil-Chemie,  1902,  p.  464. 

f  Gianoli  (Chem.  Zeit.,  1910,  p.  105)  states  that  this  reactivity  of  the  tender 
silk  is  not  due  to  the  presence  of  stannous  salts,  but  rather  to  decomposition 
products  of  the  silk,  resulting  from  the  effects  of  oxidation  and  hydrolysis  upon 
the  silk  fibroin.  These  decomposition  products  are  soluble  in  water  and  include 
ammonia  and  other  nitrogenous  compounds.  When  exposed  to  sunlight  in  a 
vacuum  or  in  an  atmosphere  of  an  inert  gas,  the  fibre  does  not  become  tender, 
but  is  seriously  affected  when  the  exposure  is  carried  out  in  the  presence  of  air 
or  moisture. 


CHEMICAL  NATURE  AND   PROPERTIES   OF  SILK       145 

tendering  in  seven  days.  The  action  of  the  salt  is  shared  in  a 
lesser  degree  by  the  chlorides  of  potassium,  ammonium, 
magnesium,  calcium,  barium,  aluminium,  and  zinc,  and  is 
probably  due  to  chemical  dissociation.  This  fact  may  account 
for  the  stains  sometimes  found  in  skeins  of  silk  which  also 
show  a  tendering  of  the  fibre.  These  stains  have  frequently 
been  noticed,  and  thorough  investigation  has  failed  to  satis- 
factorily account  for  them.  The  salt  may  get  into  the  fibre 
through  the  perspiration  of  the  workmen  handling  the  goods, 
or  through  a  variety  of  other  causes. 


FIG.  45. — Raw  Silk  in  Schweitzer's  Reagent.     (Xioo.)     (After  Herzog.) 

A  concentrated  solution  of  basic  zinc  chloride  readily  dis- 
solves the  silk  fibre.  On  diluting  this  solution  with  water  a 
flocculent  precipitate  is  obtained  which  is  soluble  in  ammonia, 
and  the  latter  solution  has  been  employed  for  coating  vegetable 
fibres  with  silk  for  the  production  of  certain  so-called  "  artificial 
silks."  An  acid  solution  of  zinc  chloride  acts  in  the  same 
manner.  Solutions  of  copper  oxide  or  nickel  oxide  in  ammonia 
also  act  as  solvents  towards  silk.  The  latter  solution  can  be 
employed  for  separating  silk  from  cotton,  the  silk  being  readily 


146  THE  TEXTILE  FIBRES 

and  completely  soluble  in  a  boiling  solution  of  ammoniacal 
nickel  oxide,  whereas  cotton  loses  less  than  i  per  cent  of  its 
weight.  A  boiling  solution  of  basic  zinc  chloride  (1:1)  will, 
dissolve  silk  in  one  minute,  while  cotton  under  the  same  treat- 
ment loses  only  0.5  per  cent,  and  wool  only  1.5  to  2  per  cent. 
Silk  is  also  soluble  in  Schweitzer's  reagent  (ammoniacal  copper 
oxide),  and  in  an  alkaline  solution  of  copper  sulphate  and 
glycerin.  The  latter  is  used  to  separate  silk  from  wool  and  cotton ; 
and  the  following  solution  is  recommended:  16  grams  copper 
sulphate,  10  grams  glycerin,  and  150  c.c.  of  water.  After 
dissolving,  add  a  solution  of  caustic  soda,  until  the  precipitate 
which  at  first  forms  is  just  redissolved.  Chlorin  destroys 
silk,  as  do  other  oxidizing  agents,  unless  employed  in  very 
dilute  solutions  and  with  great  care.  Strong  solutions  of 
stannic  chloride  (70°  Tw.)  will  dissolve  silk,  an  action  which 
should  be  borne  in  mind  when  mordanting  and  weighting  silk 
with  this  salt.  Silk  also  absorbs  sugar  to  a  considerable 
degree,  and  this  substance  may  be  employed  as  a  weighting 
material  for  light-colored  silks  on  this  account. 

(e)  Action  of  Dyestuffs. — Towards  coloring  matters  in  gen- 
eral, silk  exhibits  a  greater  capacity  of  absorption  than  perhaps 
any  other  fibre.  It  also  absorbs  dyestuffs  at  much  lower  tem- 
peratures than  does  wool. 

As  silk  is  evidently  an  amino-acid,  it  possesses  distinct 
chemical  characteristics;  that  is  to  say,  it  exhibits  both  acid 
and  basic  properties  in  a  manner  similar  to  wool.  Like  the 
latter  fibre  (see  p.  72),  it  is  probable  that  the  active  chemical 
groups  in  silk  have  considerable  influence  on  its  dyeing  proper- 
ties,* especially  with  reference  to  acid  and  basic  dyes,  for  it  has 

*  Sansone  (Rev.  Gen.  Mat.  Col.,  1911,  p.  194)  states  that  if  silk  is  treated  cold 
for  two  or  three  minutes  with  90  per  cent  formic  acid  solution  it  rapidly  swells, 
softens,  and  becomes  viscous.  On  washing,  however,  it  gradually  returns  to 
approximately  its  original  condition,  but  shows  a  greater  elasticity  and  in  some 
cases  a  higher  lustre  after  drying.  If  the  silk  is  allowed  to  contract  during  its 
immersion  in  the  formic  acid  a  linear  contraction  of  8  to  12  per  cent  is  produced; 
there  is  no  loss  in  tensile  strength  except  in 'the  case  of  low-grade  waste  silks  which 
are  occasionally  seriously  weakened.  From  comparative  dye  tests  it  would  seem 
that  the  treated  silk  has  a  greater  affinity  for  substantive  dyestuffs  and  for  metallic 
mordants.  This  result  was  confirmed  with  treated  silk  which  had  been  subse- 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK        147 

been  shown  *  that  if  these  active  molecular  groups  are  rendered 
inactive  by  acetylation  or  otherwise,  the  dyeing  properties 
of  the  silk  are  accordingly  altered. 

6.  Tussah  Silk  presents  a  number  of  differences,  both  physical 
and  chemical,  from  ordinary  silk.  It  has  a  brown  color  and 
is  considerably  stiffer  and  coarser.  It  is  less  reactive,  in  gen- 
eral, towards  chemical  reagents,  and  consequently  presents 
more  difficulty  in  bleaching  and  dyeing.  Tussah  silk  requires 
a  much  more  severe  treatment  for  degumming  than  cultivated 
silk,  and  the  boiled-off  liquor  so  obtained  is  of  no  value  in 
dyeing. 

According  to  analyses  of  Bastow  and  Appleyard,f  raw  tus- 
sah  silk  gives  the  following  results: 

Per  Cent. 

Soluble  in  hot  water 21 . 33 

Dissolved  by  alcohol  (fatty  acid) 0.91 

Dissolved  by  ether o .  08 

Total  loss  on  boiling  off  with  i  per  cent  solution  of 

soap 26 . 49 

Mineral  matter 5-34 

These  same  observers  consider  that  the  fibroin  of  tussah  silk 
differs  chemically  from  that  of  ordinary  silk,  as  it  is  not  so 
readily  acted  on  by  solvents.  In  order  to  obtain  pure  tussah 
fibroin,  the  silk  should  be  boiled  repeatedly  with  a  i  per  cent 
solution  of  soap,  washed  with  water,  extracted  with  hydro- 
chloric acid;  and  after  again  washing  with  water  and  drying, 
extracted  successively  with  alcohol  and  ether.  Tussah  fibroin 
purified  in  this  manner  shows  the  following  composition: 

Per  Cent. 

Carbon 47 .18 

Hydrogen 6 . 30 

Nitrogen 16 . 85 

Oxygen 29 . 67 

quently  neutralized  with  sodium  carbonate  solutions,  thus  proving  that  the 
increased  affinity  is  not  caused  by  free  formic  acid  remaining  in  the  fibre,  but  by 
change  in  the  physical  nature  of  the  silk  itself.  With  basic  and  acid  dyes  the 
increase  in  affinity  is  much  less  marked.  Many  artificial  silks,  and  more  especially 
viscose  silk,  show  a  similar  change  in  dyeing  properties  after  a  formic  acid  treat- 
ment but  an  immersion  of  several  hours  is  necessary  to  produce  the  effect. 

*  Suida,  Farber-Zeit.,  1905. 

t  Jour.  Soc.  Dyers'  6*  CoL,  vol.  4,  p.  88. 


148 


THE  TEXTILE  FIBRES 


These  figures  are  exclusive  of  0.226  per  cent  of  ash.  Apple- 
yard  gives  the  following  analysis  of  the  ash  from  raw  tussah 
silk. 

Per  Cent. 

Soda,  Na2O 1 2 . 45 

Potash,  K2O 31 . 68 

Alumina,  A12O3 i .  46 

Lime,  CaO 13-32 

Magnesia,  MgO 2.56 

Phosphoric  acid,  PzOs 6 . 90 

Carbonic  acid,  COz 11.14 

Silica,  SiO2 9 . 79 

Hydrochloric  acid,  Cl 2 . 89 

Sulphuric  acid,  SOs 8.16 

The  presence  of  sulphates  in  this  ash  is  somewhat  remark- 
able, as  this  constituent  does  not  occur  in  ordinary  silk.  The 
occurrence  of  alumina  is  also  remarkable,  as  this  element  is 
seldom  a  constituent  of  animal  tissues.  As  the  amount  of  ash 
of  purified  fibroin  of  both  common  silk  and  tussah  silk  is  very 
much  lower  than  that  of  the  raw  silks,  it  is  to  be  considered 
probable  that  most  of  the  mineral  matter  found  is  derived 
from  adhering  impurities,  and  is  not  a  true  constituent  of  the 
silk  itself. 

Tussah  silk  is  scarcely  affected  by  an  alkaline  solution  of 
copper  hydrate  in  glycerin,  whereas  ordinary  silk  is  readily 
soluble  in  this  reagent.* 

The  following  table  exhibits  the  principal  differences  between 
true  silk  and  tussah  silk:f 


Reagent. 

Mulberry  Silk. 

Tussah  Silk. 

Hot  caustic  soda  (10%) 

Dissolves  in  1  2  minutes 

Requires  50  minutes  for 
solution 

Cold  hydrochloric  acid  (sp.gr. 
1.16) 
Cold  cone,  nitric  acid 
Neutral  solution  of  zinc  chloride 
(sp.gr.  1.725) 
Strong  chromic  acid  solution  in 

Dissolves  very  rapidly 

Dissolves  in  5  minutes 
Dissolves  very  rapidly 

Dissolves  very  rapidly 

Only  partially  dissolves, 
in  48  hours 
Dissolves  in  10  minutes 
Dissolves  but  slowly 

Dissolves  very  slowly 

water 

*  Filsinger,  Chem.  Zeit.,  vol.  20,  p.  324. 

t  Bastow  and  Appleyard,  Jour.  Soc.  Dyers'  6*  Col.,  vol.  4,  p.  89. 


CHEMICAL  NATURE  AND   PROPERTIES  OF  SILK      149 


While  the  fibre  of  mulberry  silk  presents  the  appearance  of  a 
structureless  thread,  and  rarely  exhibits  signs  of  distinct  striation, 
tussah  (as  well  as  other  "  wild  "  silks)  is  made  up  of  bundles 
of  delicate  fibrillae,  varying  in  diameter  from  0.0003  to  0.0015 
mm.,  so  that  the  fibre  as  a  whole  presents  a  striated  appearance. 
Also  the  cross-section  *  of  tussah  silk  is  considerably  larger 
than  that  of  mulberry  silk,  and  is  more  flattened;  it  also 
exhibits  numerous  fine  air-tubes.  The  following  table  exhibits 
the  difference  in  the  microscopic  appearance  of  various  kinds 
of  raw  silk;  the  diameter  is  expressed  in  ^  =  thousandths  of  a 
millimeter  :f 


Variety  of  Silk. 

Diameter, 
M- 

Appearance. 

Broad  Side. 

Narrow  Side. 

True  silk,  Bombyx 

20  to  25 

White      or      yellowish; 

White     or     yellowish; 

mori 

shiny 

shiny 

Senegal     silk,     B. 

30  to  35 

Shining      yellowish      or 

Gray,  brown,  or  black, 

faidkerbi 

brownish  white,  or  pale 

with     occasionally 

yellow,    gray,    brown, 

lighter  shades 

and  occasionally  bluish 

white 

Ailanthus  silk,  A  tta- 

40  to  50 

Shining  yellowish  white, 

Dirty  gray  or  brown  to 

cus  cynthia 

with  yellow,  brown,  or 

black,  with  green,  yel- 

brownish gray  spots 

low,    red,    violet,    or 

blue  spots 

Yama-mai    silk, 

40  to  50 

Bluish  white  with  dark 

Glaring  and  fine  colors, 

Anther  aa    yama- 

blue,    blue    and    black 

with    dark    or   black 

mai 

shades 

shades 

Tussah    silk,    Atta- 

50  to  55 

Irregular    in    thickness. 

Dark  gray,  with  pink  or 

cus  selene 

Thickest     parts     with 

light  green  spots 

gray   and    blue    spots; 

thinner     parts     bluish 

white,     yellow,     or 

orange-red 

Tussah    silk,    An- 

60  to  65 

Similar    to    above,    but 

Similar  to  above 

thercea  mylitta 

spots  orange-red,   red, 

or  brown 

The  cocoon-threads  of  wild  silks  possess  greater  elasticity 
and  tensile  strength,  as  would  naturally  be  expected  from  their 

*  Filsinger,  vide  supra.          f  Hohnel,  Jour.  Soc.  Chem.  Ind.,  vol.  2,  p.  172.      - 


150 


THE  TEXTILE  FIBRES 


greater  thickness.     The  following  table  gives  the  elasticity  and 
breaking  strain  of  the  principal  varieties  of  silk: 


Variety  of  Silk. 

Elasticity, 
Per  Cent. 

Breaking 
Strain,  Grams. 

Mulberry  (Bombyx  wiori)  

IT.  .T, 

4-  $ 

Tussah  (Anther  &a  mylitta) 

10    I 

12   8 

Eria  (Attacus  ricini) 

I'C-.Q 

4   O 

Muga  (Anlhercea  assama)  

21  .  7 

6.7 

Atlas  (Attacus  alias) 

10    I 

c.6 

Ailanthus  (Atlacns  cynthia)  

22  .  ? 

4.9 

Yama-mai  

2Z    O 

12.8 

Attacus  Selene 

2O   O 

5  6 

Anther  (Ea  pernyi  

10-  I 

8.1 

FIG.  46. — Fibre  from  Penna  nobilis.     (Xioo.)     (Micrograph  by  author.) 

7.  Byssus  Silk. — This  is  also  known  as  "  sea-silk,"  and  is 
obtained  from  a  marine  mollusc,  Penna  nobilis,  and  related 
varieties.  The  shell-fish  possesses  a  long  slender  gland  which 
secretes  woolly  fibres  known  as  the  Byssus  or  "  beard."  These 


CHEMICAL  NATURE  AND  PROPERTIES  OF  SILK       151 

fibres  are  of  a  brown  color  and  are  4  to  6  cm.  in  length.  The 
brown  color  is  said  to  be  due  to  an  external  covering  which 
when  removed  leaves  a  colorless  fibre.  Sea-silk  is  somewhat 
used  in  southern  Italy  and  in  Normandy  for  the  making  of 
various  ornamental  braided  articles.  Though  this  fibre  some- 
what resembles  silk  in  appearance,  it  is  easily  distinguished 
by  the  presence  of  natural  rounded  ends.  The  fibres  vary 
considerably  in  diameter  (10  to  100  JJL)  and  are  elliptical  in  cross- 
section  (see  Fig.  46),  and  are  often  twisted.  Fine  longitudinal 
striations  are  apparent,  but  as  the  fibre  is  solid  no  empty  lumen 
or  air  canals  are  present.  The  finer  fibres  are  smooth,  but  the 
coarser  ones  are  rough  and  corroded.  Frequently  very  delicate 
fibrils  are  to  be  observed  branching  from  the  larger  fibres.* 

*  Another  animal  fibre  of  a  somewhat  silk-like  nature  is  the  so-called  "sinew 
fibre,"  This  product  is  obtained  from  sinews  which  consists  of  fibrous  con- 
nective tissue  made  up  of  wavy  elements  united  in  bundles.  Hanausek  (Micros- 
copy of  Technical  Products,  p.  150)  calls  attention  to  the  fact  that  sinew  fibre 
was  utilized  in  ancient  times,  the  Israelites  using  a  yarn  twisted  from  sinews 
under  the  name  of  "gidden"  for  their  religious  rites.  In  recent  years  sinew  fibre 
has  been  spun  into  yarns  by  mixing  with  wool  or  hemp.  The  fibre  is  very. silky 
in  lustre  and  varies  much  in  length  (from  3  to  18  cm.).  Such  yarns  have  great 
tensile  strength  and  are  rough  in  feel. 


CHAPTER  IX 

THE   VEGETABLE   FIBRES 

i.  General  Considerations. — The  basis  of  all  vegetable 
fibres  is  LO  be  found  in  cellulose,  a  compound  belonging  to  a 
class  of  naturally  occurring  substances  known  as  carbohydrates. 
It  is  seldom,  however,  that  cellulose  actually  occurs  in  the 
plant  in  the  free  condition,  but  is  usually  associated  or  chem- 
ically combined  with  other  substances,  of  which  the  principal 
are  fatty  and  waxy  matters,  coloring  matters,  and  tannins, 
and  a  rather  indefinite  group  of  so-called  pectin  matters,  which 
appear  to  be  more  or  less  oxidized  or  acid  derivatives  of  the 
carbohydrates.  The  fibres  may  be  seed-hairs,  such  as  the 
different  varieties  of  cotton,  cotton-silk,  etc.;*  or  bast  fibres, 
which  include  those  obtained  from  the  cambium  layer  of  the 
dicotyledonous  plants,f  such  as  flax,  hemp,  jute,  ramie,  etc.; 
or  vascular  fibres, J  which  include  those  obtained  chiefly  from 

*  In  a  certain  sense,  the  cocoanut  fibre  (coir)  may  be  included  under  the 
class  of  seed-hairs. 

fThe  terms  "dicotyledonous"  and  " monocotyledonous "  refer  to  plants  the 
seeds  of  which  have  two  lobes  and  one  lobe  respectively.  A  dicotyledonous 
plant  is  also  an  exogen  or  outside  grower,  familiar  examples  of  which  are  ordinary 
trees  or  shrubs.  Monocotyledonous  plants,  on  the  other  hand,  are  endogens,  or 
inside  growers,  such  as  grasses,  palms,  lilies,  etc.  The  stalk  of  the  monocotyled- 
onous plant  is  really  the  residue  of  the  successive  leaf-sheaths,  whereas  the 
stalk  of  the  dicotyledonous  plant  is  a  separate  growth  entirely  distinct  from 
the  leaf. 

I  In  China  there  is  an  example  of  a  spinning  fibre  composed  of  the  leaf-hairs 
of  a  plant.  The  latter  apparently  belongs  to  the  Xeranthemum,  and  its  leaves 
are  covered  with  a  thick  mass  of  long  hairy  fibres,  which  are  easily  separated 
from  the  leaf  when  dried  (see  Wiesner,  Die  Rohstoije  des  Pftanzenreiches,  p.  167). 

152 


THE  VEGETABLE  FIBRES  153 

the    leaf-tissues    of    the    monocotyledonous    plants,    such    as 
phormium,  agave,  aloe,  etc.* 

Anatomically  considered,  the  plant  fibres  may  be  divided 
into  six  different  classes  (Hohnel) : 

1.  Single-cell    plant-hairs,  such    as  cotton,  vegetable  silk, 
and  vegetable  down. 

2.  Fibres  consisting    of  several    cells,   such  as  pulu  fibre, 
elephant-grass,  and  cotton-grass. 

3.  Bast  fibres,  such  as  flax,  hemp,  jute,  ramie,  etc. 

4.  Dicotyledonous   bast  fibres,  such   as  linden  bast,  Cuba 
bast,  etc. 

5.  Monocotyledonous  vascular   fibres,  such    as  sisal  hemp, 
aloe  hemp,  pineapple  fibre,  cocoanut  fibre,  etc. 

6.  Monocotyledonous  sclerenchymous  fibres,  such  as  Manila 
hemp,  New  Zealand  flax,  etc. 

Depending  on  the  portion  of  the  plant  from  which  the  fibre 
is  derived,  the  following  classification  may  be  used: 

1.  Seed  fibres,  growing  from   the  seeds  or  seed-capsule's  of 
certain  plants,  and  including  cotton,  vegetable  silk,   etc. 

2.  Stem  fibres,  growing  in  the  bast  of  certain  dicotyledonous 
plants,  and  including  flax,  hemp,  jute,  etc. 

3.  Leaf  fibres,    occurring   in   the    leaves    of  a  number   of 
monocotyledonous  plants,  and  including  New  Zealand  hemp, 
Manila  hemp,  aloe,  etc. 

4.  Fruit  fibres  of  which  the  sole  member  worth  mentioning 
is  the  cocoanut  fibre,  f 

There  is  considerable  difference  to  be  observed  between  the 
anatomical  structure  of  seed-hairs  and  that  of  bast  fibres. 
Seed-hairs  are  known  botanically  as  plumose  fibres,  and 
usually  consist  of  a  unicellular  fibre  exhibiting  only  a  single 
solid  apex,  the  other  end  being  attached  to  the  seed.  •  Exter- 
nally they  appear  to  be  covered  with  a  thin  skin  or  cuticle 

*  There  is  peculiar  instance  in  which  the  entire  plant  is  used  as  the  fibre; 
this  is  sea-grass  or  sea- wrack  (Zostera  marina).  However,  it  can  scarcely  be 
considered  as  a  textile  fibre,  as  it  is  almost  altogether  employed  for  stuffing  and 
packing. 

t  Zipser,  Textile  Raw  Materials,  p.  8. 


154  THE  TEXTILE  FIBRES 

which  differs  essentially  from  the  remaining  cellulose  in  that 
it  is  not  dissolved  by  treatment  with  sulphuric  acid.  The 
cell- walls  vary  considerably  in  their  thickness,  and  are  struc- 
tureless and  porous.  Through  the  centre  of  the  fibre  runs  a 
hollow  canal  called  the  lumen.  Usually  the  dried  fibre  is 
flattened  into  the  form  of  a  band,  so  that  in  cross-section  the 
lumen  appears  as  a  line.  Bast  fibres,  on  the  other  hand,  con- 
sist of  completely  enclosed  tubes,  each  end  being  pointed. 
Each  individual  fibre  is  multicellular,  the  cells  being  long  and 
usually  polygonal  in  cross-section.*  The  cell-walls  are  usually 
rather  thick,  and  the  cross-section  instead  of  being  flat  and 
narrow  is  broad  and  more  or  less  rounded.  The  inner  wall  is 
frequently  covered  with  a  thin  layer  of  dried  protoplasm.  One 
of  the  most  characteristic  appearances  of  the  bast  fibres  is  the 
occurrence  of  dislocations  or  joints  throughout  the  length  of 
the  fibre  (see  Fig.  47).  These  dislocations  show  the  property 
of  becoming  more  deeply  colored  than  the  rest  of  the  fibre 
when  treated  with  a  solution  of  chlor-iodide  of  zinc.  These 
knots  or  joints  generally  show  thicker  overlying  transverse 
fissures,  between  which  lie  small  short  discs  arranged  on  edge. 
The  joints  disappear  altogether  in  the  monocotyledonous 
fibres;  they  are  also  lacking  on  many  true  bast  fibres,  such  as 
jute,  linden  bast,  etc.,  but  occur  in  hemp,  flax,  ramie,  etc. 

Bast  fibres  are  the  long,  tough  cells  found  in  the  barks  and 
stems  of  various  plants.  The  cell-walls  of  these  fibres,  are 
usually  partially  changed  from  pure  cellulose  into  lignin  and  are 
thickened.  There  is  usually  a  considerable  amount  of  foreign 
matter  also  contained  in  the  cell-wall,  and  often  this  becomes 
sufficiently  characteristic  to  serve  as  a  means  of  identifying  the 
various  fibres  by  the  application  of  chemical  reagents.  Fibres 
which  contain  only  pure  cellulose  are  colored  blue  when  treated 


*  The  bast  or  vascular  bundles  consist  of  two  parts,  the  phloem  and  the  xylem. 
As  a  rule,  the  phloem  occurs  nearer  the  outside  of  the  plant,  while  the  xylem  forms 
the  principal  structural  part  of  the  inside  portion  of  the  plant.  The  fibres  in 
the  phloem  are  usually  rather  easily  detached  and  form  the  commercial  product, 
while  those  occurring  in  the  xylem,  as  a  rule,  cannot  be  readily  separated  by 
mechanical  means  from  the  woody  tissue  in  which  they  are  imbedded. 


THE  VEGETABLE   FIBRES  155 

with  the  iodin-sulphuric  acid  reagent  (see  Chapter  XVIII), 
while  fibres  containing  lignin  are  colored  yellow  to  brown  by 
the  same  test.*  Unlike  seed-hairs,  the  individual  cells  of  bast 
fibres  are  not  of  sufficient  length  for  use  in  spinning,  but  as  they 


FIG.  47.  FIG.  48. 

FIG.   47. — A  Typical   Bast   Fibre  (X35°)>  showing   the   Jointed   Structure   or 
Dislocations  at  D.     (Micrograph  by  author.) 

FIG.  48.— A  Bundle  of  Bast  Fibres.     (X400.)     (After  Lecomte.) 

are  held  together  with  considerable  firmness  to  form  bundles 
of  great  length,  they  are  utilized  in  this  form. 

t  The  most  satisfactory  test  for  lignification  is  that  given  by  Maule  (Beitr. 
Wiss.  Bot.,  i goo,  vol.  4,  p.  166),  as  follows:  Sections  are  soaked  for  about  five 
minutes  in  a  one  per  cent  solution  of  potassium  permanganate,  and  after  washing 
in  water,  are  soaked  for  two  to  three  minutes  in  dilute  hydrochloric  acid,  and 
finally  in  ammonia.  All  lignified  parts  assume  a  red  color  by*  this  treatment. 


156 


THE  TEXTILE  FIBRES 


Wiesner  gives  the  following  table  showing  the  length  of  the 
raw  fibre  and  the  dimensions  of  the  cells  composing  them. 


Fibre. 

Length  of 
Raw,  Fibre 
cm. 

Length  of 
Cells, 
mm. 

Breadth  of  Cells. 

Min.  ft. 

Max.  n. 

Aver.  M. 

Tillandsia  fibre  

2-22 
IO-4O 
50-QO 

80-110 
60-70 

50-150 
150-300 
100-180 

100-120 
80-IOO 
20-30 
40-50 
2O-I4O 
100-300 
150-300 
40-90 
20-50 
IOO-IIO 

0.2-0.5 
1.5-1.9 
o.  i-i  .6 
2-5-5-6 
o.  i-i  .6 
1.5-4.0 
o  .  8-4  .  i 
0.9-4.7 
1.1-3.2 
0.8-2.  3 
0.7-3.0 
1-3-3-7 

2  .  0~4  .  O 

o  .  8-4  .  i 
o  .  8-4  .  i 
4  .  o-i  2  .  o 

0.5-6.9 
1.4-6.7 

22  .O 
8.0 
40-5 

35-r 
18.2 
28.4 
25-0 
20-30 
20-30 
10-30 
10-25 
10-56 
30-45 

I  .  1-2.6 

1-5-3-5 
0.9-2.1 

1-2 
0.4-5.1 

4 

I  .  0-4  .  2 
1.0-2.2 

o  .  4-0  .  9 

6 

9 
14.7 
8 
8 
8 
10 

12 

9 

15 

18 
15 

12 

16  , 
16 

20 
2O 
27 
40 

16 
19.2 

17 
11.9 
20.  i 

20 

19 
12 
20 
19 

49 
33 

17 
9 
17 
8 

15 
15 
16.8 
29 

20 
2O 
21 
21 
24 
25 
25 
24 

25 
32 
32 
41 
42 
42 
80 
12.6 

27-9 
27.1 

22 
29.9 

37-8 
29 
42 
44 
33 
92 
50 

25 
14 
24 
29 

15 
13 
16 

16 
16 
15 

16 

20 
20 

50 

25-2 
25-9 
18.5 
29.4 
29.9 

38 

15 

20 

12 

21 
20 
17 

16 

Esparto  grass                        

Cordid  Idtifolid 

Phormium  tenax  

Abelmoschus  tetraphvllos      

Bduhinid  rdccwiosd 

Jute  (Corchorus  capsularis)  

Thcspcsid  Idtnpds                    

Urcnd  sinudtd 

Sidd  T6tusd     ...        

CdlotTopis  gigdntcd  (bast) 

Aloe  perfolidtd  

Flax  (Linum  usitdtissimum)  
Hemp  (Cdnndbis  sdtivo) 

Jute  (Corchorus  olitorius)  
Hibiscus  cdnnobinus   .                  ... 

Sunn  hemp  (Crotolaria  junced)  
Bromelia  karatas   

China  grass  (Boshmcrid  nivcd) 

Ramie  (Boehmeria  tenacissima)  
Cotton  (Gossypium  bdrbddense). 

4.05 
3.51 
1.82 

2.84 

2.50 

2-3 

2~3 

1  '       (G.  conglomerdtuni)  

'  '       (G.  herbdceum)      

(G.  dcumindtuni)  

'  '       (G.  arboreum)  

Cotton  wool  (Bombax  heptaphyllum)  . 
Vegetable  silk  (Cdlotropis  gigantea)  .  . 
(Asdepids)  
'  '            (Mdrsdenid} 

1  '            (Strophdntus) 

(Bediimontid)  

Linden-bast 

Slcrculid  villosd 

Holoptelea  integrifolid  

Kydid  cdlycind   

Ldsiosyphon  spcciosus 

Sponid  Wightii  

Panddnus  odordtissimus  
Pita  fibre 

16 

12 

21 
2O 

Coir  fibre  

THE  VEGETABLE   FIBRES 


157 


Vetillard  gives  a  somewhat  similar  table  as  follows: 


Name. 

Length  in  (mm.). 

Breadth  (in  M). 

Ratio  of 
Breadth 
to  Length. 

Min. 

Max. 

Mean. 

Min. 

Max. 

Mean. 

Linen 

4 
5 
4 
4 
60 

4 

2 

5 
5 
10 

2 
I  .  2 

i-5 
3 

o-S 
i-3 
3 
2-5 
0.8 

5 
o-5 
i-5 
i-5 
3 

66 
55 
iQ 
57 
250 

25 

12 

9 
16 
18 
40 
6 
5 
5 
6 

3 
3-5 
4-5 
9 

10 

2-5 
15 
6 
6 
4 

12 

25 
2O 
IO 

27 
120 
IO 

8 
5 

IO 
IO 

5 

2 
2 

5 
2 

i-5 

2.5 

5 
5 

2 

9 

4 
3 
2-5 
6 

5 
3 
3 
2-5 
2-5 
i-5 
0.7 

15 
16 

12 
20 

25 
IO 

20 

14 
14 
2O 
10 
17 

7 

12 

4 
20 
8 

10 
IO 

IS 

20 

16 
20 
16 
16 

IO 
12 
IO 
12 

37 
50 
26 
70 
80 

50 
25 

36 

33 
20 

25 

20 
3° 

18 

20 

8 
32 
16 
20 
20 
26 
32 
32 
40 

24 

28 

13 
20 
16 
24 

2O 

22 

16 
50 
50 
30 
30 
15 

20 
30 

21 

16 

22.5 

12OO 
IOOO 

620 

550 

2400 

350 
•  260 

330 
500 

330 

240 

125 
90 
500 
90 
125 
1  60 
830 

210 
150 
550 
170 

150 
IOO 

250 
1  80 
150 

120 
230 
1  60 
130 

35 

Hemp  (Cannabis  saliva)  
Hop  fibre  (Hnmulus  lupiilus)  
Nettle  fibre  (Urtica  dioica)  .  . 

Ramie  (Urtica  nivea)  
Fibre  of  paper  mulberry  

Sunn  hemp  (Crotalaria  jimcea)  
Broom-grass  (Sarothamnus  vulgaris) 
Feather-grass  (Spartiumjunceuni)  .  . 
White  clover  (Melilotus  alba)  
Cotton 

Gambo  hemp  (Hibiscus  cannabinus) 
Linden-bast  (Tilia  enrop&a)  
Jute  (Corchorus  capsularis)            .    . 

Lace  bark  (Lagetta  lintearia)  
Willow  (Sdix  alba)  

22 
12 

15 
6 
24 
13 

16 
15 

20 

24 
24 
28 
2O 

24 
II 

16 

12 

2O 

Esparto  .  .  

L\s(Eum  spartum 

Pineapple  fibre  

Silk-grass  (Bromelia  karatas)  
Wild  pineapple  (Bromelia  pinguin) 
New  Zealand  flax  (Phormium  lenax) 
Yucca  fibre  
Sansevieria  fibre                    

Pita  (Agave  americana)  

Manila  hemp  (Musa  textilis)  
Banana  (Musa  paradisaica)  . 

Date  palm  (Phoenix  dactylifera)  .... 
Talipot  pa\m(Corypha  umbraculifera) 
Oil  palm  (Elais  guineensis)  
Raphia  t&digera 

2 

i-5 
IS 
i-5 

i 
0.4 

6 
5 
3-5 
3 
3 
i 

Ita  palm  (Mauritia  flexuosa)  

Coir  fibre  (Cocos  nucifera)  

2.  Classification. — Perhaps  the  most  systematic  and  com- 
plete enumeration  of  the  various  vegetable  fibres,  together 
with  a  classification  of  their  technical  uses,  is  that  given  by 
Dodge,*  from  which  the  following  abstract  is  taken. 

*  Useful  Fibre  Plants  of  the  World 


158  THE  TEXTILE   FIBRES 

STRUCTURAL  CLASSIFICATION. 
A.    FlBROVASCULAR  STRUCTURE. 

1.  Bast  fibres. — Derived    from    the   inner   fibrous   bark   of 
dicotyledonous  plants  or  exogens,  or  outside  growers.     They 
are  composed  of  bast-cells,  the  ends  of  which  overlap  each  other, 
so  as  to  form  in  mass  a  filament.     They  occupy  the  phloem 
portion  of  the  fibrovascular  bundles,  and  their  utility  in  nature 
is  to  give  strength  and  flexibility  to  the  tissue. 

2.  Woody  fibres. 

(a)  The   stems   and    twigs   of   exogenous   plants,   simply 
stripped  of    their  bark   and  used    entire,   or    separated    into 
withes  for  weaving  or  plaiting  into  basketry. 

(b)  The   entire  or  subdivided  roots  of   exogenous  plants, 
to  be  employed  for  the  same  purpose,  or  as  tie  material,  or  as 
very  coarse  thread  for  stitching  or  binding. 

(c)  The  wood  of  exogenous  trees  easily  divisible  into  layers 
or  splints  for  the  same  purposes,  or  more  finely  divided  into 
thread-like  shavings  for  packing  material. 

(d)  The  wood  of  certain  soft  species  of  exogenous  trees, 
after  grinding  and  converting  by  chemical  means  into  wood- 
pulp,  which  is  simple  cellulose,  and  similar  woods  more  care- 
fully prepared  for  the  manufacture  of  artificial  silk. 

3.  Structural  fibres. 

(a)  Derived  from  the  structural  system  of  the  stalks,  leaf- 
stems,  and  leaves,  or  other  parts  of  monocotyledonous  plants, 
or  inside  growers,  occurring  as  isolated  fibrovascular  bundles, 
and  surrounded  by  a  pithy,   spongy,  corky,  or  often  a  soft, 
succulent,  cellular  mass  covered  with  a  thick  epidermis.     They 
give  to  the  plant  rigidity  and  toughness,  thus  enabling  it  to 
resist  injury  from  the  elements,  and  they  also  serve  as  water- 
vessels. 

(b)  The    whole    stems,  or  roots,  or  leaves,  or  split  and 
shredded  leaves  of  monocotyledonous  plants. 

(c)  The  fibrous  portion  of  the  leaves  or  fruits  of  certain 
exogenous  plants  when  deprived  of  their  epidermis  and  soft 
cellular  tissue. 


THE  VEGETABLE   FIBRES  159 

B.  SIMPLE  CELLULAR  STRUCTURE. 

4.  Surface  fibres. 

(a)  The  down  or  hairs  surrounding  the  seeds,  or  seed  en- 
velopes, or  exogenous  plants,  which  are  usually  contained  in  a 
husk,  pod,  or  capsule. 

(b)  Hair-like  growths,  or  tomentum,  found  on  the  surf  aces  of 
stems  and  leaves,  or  on  the  leaf -buds  of  both  divisions  of  plants. 

(c)  The  fibrous  material  produced  in  the  form  of  epidermal 
strips  from  the  leaves  of  certain  endogenous  species,  as  the  palms. 

5.  Pseudo-fibres,  or  false  fibrous  material. 

(a)  Certain  of  the  mosses,  as  the  species  of  the  Sphagnum, 
for  packing  material. 

(b)  Certain  leaves  and  marine  weeds,  the  dried  substance 
of  which  forms  a  more  delicate  packing  material. 

(c)  Seaweeds  wrought  into  lines  and  cordage. 

(d)  Fungus  growths,  or  the  mycelium  of  certain  fungi  that 
may  be  applied  to  economic  uses,  for  which  some  of  the  true 
fibres  are  employed. 

The  bast  fibres  *  are  clearly  defined,  and  all  such  fibres  when 
simply  stripped  are  similar  in  form  as  to  outward  appearance, 
differing  chiefly  in  color,  fineness,  and  strength.  An  example 
of  a  fine  bast  fibre  is  the  ribbons  or  filaments  of  hemp.  The 
woody  fibresf  are  only  fibrous  in  the  broad  sense,  as  their  cel- 
lulose filaments  are  very  short  and  are  easily  separated  and  all 
extraneous  matter  removed  by  chemical  means,  as  for  the  manu- 
facture of  paper-pulp  or  of  artificial  silk.  The  structural  fibres  J 

*  The  bast  fibres  are  derived  from  the  stems  of  exogenous  plants,  such  as 
trees,  shrubs,  the  climbing  vines,  and  herbaceous  vegetation  generally. 

f  The  greater  number  of  woody  fibres  are  merely  wood  in  the  form  of  flexible 
slender  twigs  or  osiers  that  are  useful  for  making  baskets;  or  the  larger  branches 
may  be  split  or  subdivided  into  strips,  withes,  or  flat  ribbons  of  wood  for  making 
coarser  baskets.  The  softer  woods  still  further  divided  give  the  product  known 
as  "excelsior,"  which  can  only  claim  a  place  in  the  list  of  fibres  on  account  of  its 
use  in  upholstery  or  packing. 

|. Among  the  many  forms  of  the  structural  fibres  may  be  enumerated  the 
following:  The  stiff,  white,  or  yellowish  fibres  forming  the  structure  of  all  fleshy- 
leaved  or  aloe-like  plants,  as  the  century  plant,  the  yuccas,  agave,  and  pineapple, 
or  the  fleshy  trunk  of  the  banana;  the  coarser  bundles  of  stiff,  fibrous  substance 
which  gives  strength  to  the  trunks,  leaf,  stem,  and  even  the  leaves  of  palms, 
such  as  piassave,  derived  from  the  dilated  margins  of  the  petioles  of  a  palm; 


160  THE  TEXTILE  FIBRES 

are  found  in  many  forms  differing  widely  from  each  other,  and 
the  surface  fibres  *  are  still  more  varied  in  form. 

ECONOMIC  CLASSIFICATION.! 

A.  SPINNING  FIBRES.  J 
i.  Fabric  fibres: 

(a)  Fibres  of  the  first  rank  for  spinning  and  weaving  into 
fine  and  coarse  textures   for  wearing  apparel,  domestic  use,  or 

stiff  fibres  extracted  by  maceration  from  the  bases  of  the  leaf-stems  of  the  cabbage 
palmetto,  or  the  shredded  leaves  of  the  African  fan  palm,  known  as  Crin  vegetal, 
rattan  strips  and  fibrous  material  derived  from  bamboo,  the  corn-stalk,  broom- 
corn,  and  from  reeds,  sedges,  and  grasses;  still  other  forms  are  the  coir  fibre 
surrounding  the  fruit  of  the  cocoanut,  the  fibre  from  pine-needles,  and  the  fibrous 
mass  filling  the  sponge  cucumber,  which  is  a  peculiar  example  of  a  structural 
fibre  derived  from  an  exogenous  plant. 

*  Surface  fibres  may  consist  of  the  elongated  hairs  such  as  surround  the  pods 
of  the  thistle,  and  known  as  thistle-down,  or  they  may  be  fibrous  growths  around 
seed  clusters,  as  the  cotton-boll,  the  milk-weed  pod,  etc.,  or  they  may  be  the  leaf 
scales  or  tomentum  found  on  the  under  surface  of  leaves  or  epidermal  strips  of 
palm  leaves,  such  as  raffia. 

fDewey  (Y ear-Book,  Dept.  Agric.,  1903)  gives  the  following  economic  classi- 
fication of  the  vegetable  fibres: 

(1)  The  cottons,  with  soft,  lint-like  fibre  %  inch  to  2  inches  long,  composed 
of  single  cells,  borne  on  the  seeds  of  different  species  of  cotton-plants. 

(2)  The  soft  fibres,  or  bast  fibres,  including  flax,  hemp,  and  jute;    flexible 
fibres  of  soft  texture,  10  to  100  inches  in  length,  composed  of  many  overlapping 
cells  and  contained  in  the  inner  bark  of  the  plants. 

(3)  The  hard,  or  leaf,  fibres,  including  Manila,  sisal,  Mauritius,  New  Zealand 
fibres,  and  istle,  all  having  rather  stiff,  woody  fibres  i  to  10  feet  long,  composed 
of  numerous  cells  in  bundles,  borne  in  the  tissues  of  the  leaf  or  leaf-stem. 

J  The  following  table  shows  the  imports  into  the  United  States  of  various 
raw  vegetable  fibres  for  the  year  ending  June  30,  1912: 

Pounds.  Value. 

Cotton 109,780,071  $20,217,581 

Flax 21,800,000  3,778,501 

Hemp 10,014,000  1,100,273 

Istle 19,670,000  776.351 

Jute 202,002,000  7,183,385 

Kapoc 4,198,000  570,084 

Manila  hemp 137,072,000  8,000,865 

New  Zealand  flax 10,728,000  483,310 

Sisal  grass 228,934,000  11,866,843 

All  other 18,540.000  703,254 


Total 762,738,071  $54,680,447 


THE  VEGETABLE  FIBRES  161 

house-furnishing  and  decoration,  and  for  awnings,  sails,  etc. 
(The  commercial  forms  are  cotton,  flax,  ramie,  hemp,  pineapple, 
and  New  Zealand  flax.) 

(b)  Fibres  of  the  second  rank,  used  for  burlap  or  gunny, 
cotton  bagging,  woven  mattings,  floor-coverings,  and  other 
coarse  uses.  (Commercial  examples  are  coir  and  jute.) 

2.  Netting  fibres. 

(a)  Lace  fibres,  which  are  cotton,  flax,  ramie,  agave,  etc. 

(b)  Coarse  netting  fibres,  for  all  forms  of  nets,  and  for 
nammocks.     (Commercial    forms:     Cotton,    flax,    ramie,    New 
Zealand  flax,  agave,  etc.) 

3.  Cordage  fibres. 

(a)  Fine-spun  threads  and  yarns  other  than  for  weaving; 
cords,  lines,  and  twines.     (All  of  the  commercial  fabric  fibres, 
sunn,  Mauritius,  and  bowstring  hemps.  New  Zealand  flax,  coir, 
Manila,  sisal  hemps;   the  fish-lines  made  from  seaweeds.) 

(b)  Ropes   and   cables.     (Chiefly   common   hemp,    sisal, 
and  Manila  hemps,  when  produced  commercially.) 

B.  TIE  MATERIAL  (rough  twisted). 

Very  coarse  material,  such  as  stripped  palm-leaves,  the 
peeled  bark  of  trees,  and  other  coarse  growths  used  without 
preparation. 

C.  NATURAL  TEXTURES. 

1.  Tree-basts,  with  tough  interlacing  fibres. 

(a)  Substitutes  for  cloth,  prepared  by  simple  stripping 
and  pounding. 

(b)  Lace-barks,*    used    for    cravats,    frills,    ruffles,    etc., 
and  for  whips  and  thongs. 

2.  The   ribbon   or   layer   basts,    extracted   in   thin,   smooth- 
surfaced,    flexible    strips    or    sheets.     (Cuba    bast  f    used    as 
millinery  material,  cigarette  wrappers,  etc.) 

*  The  lace-bark  tree  is  the  Lagetta  lintearia,  and  grows  principally  in  Jamaica. 
The  fibre  (or  rather  fabric)  is  obtained  from  the  inner  bark,  occurring  in  con- 
centric layers  which  are  easily  detachable,  and  which  are  suited  to  the  most  deli- 
cate textiles;  when  stretched  out  they  form  a  pentagonal  or  hexagonal  mesh  very 
closely  resembling  lace. 

t  The  Cuba  bast    here  referred  to  is  the  lace-like  inner  bark  from  the  Hibis- 


162  THE  TEXTILE  FIBRES 

3.  Interlacing  structural. fibre  or  sheaths. 

(a)  Pertaining  to  leaves  and  leaf-stems  of  palms,  such  as 
the  fibrous  sheaths  found  at  the  bases  of  the  leaf-stalks  of  the 
cocoanut. 

(b)  Pertaining    to    flower-buds.     The    natural    caps    or 
hats  derived  from  several  species  of  palms. 

D.  BRUSH  FIBRES. 

1.  Brushes  manufactured  from  prepared  fibre. 

(a)  For  soft  brushes.     (Substitutes  for  animal  bristles, 
such  as  Tampico.) 

(b)  For  hard  brushes.     (Examples:    Palmetto  fibre,  pal- 
myra, kittul,*  etc.) 

2.  Brooms  and  whisks. 

(a)  Grass-like   fibres.     (Examples:    Broom-root,   broom- 
corn,  etc.) 

(b)  Bass  fibres.     (Monkey  bass,  etc.) 

3.  Very  coarse  brushes  and  brooms. 

Material  used  in  street-cleaning.     Usually  twigs  and  splints. 

E.  PLAITING  AND  ROUGH- WEAVING  FIBRES. 
i.  Used  in  hats,  sandals,  etc. 

(a)  Straw   plaits.     From   wheat,    rye,   barley,    and   rice 
straw.     (Tuscan  and  Japanese  braids.) 

(b)  Plaits   from   split   leaves,    chiefly   palms   and   allied 
forms  of  vegetation.     (Panama  hats.f) 

cus  elatus,  which  was  formerly  largely  used  for  tying  up  bundles  of  Havana  cigars. 
The  plant  also  yields  a  bast  fibre  which  is  coarse  but  very  strong^and  is  suitable 
for  the  making  of  cordage  and  coffee  bags. 

*  Kittul,  or  kittool,  fibre  is  obtained  from  the  jaggery  palm,  Caryota  urens. 
The  structural  fibre  is  brownish  black  in  color  and  lustrous,  the  filaments  being 
straight  and  smooth.  It  somewhat  resembles  horsehair  and  curls  like  coir  when 
drawn  between  the  thumb  and  nail  of  the  forefinger.  In  Ceylon  the  fibre  is  used 
for  the  manufacture  of  ropes  of  great  strength  which  are  used  for  tying  elephants. 
It  is  largely  used  for  making  brushes  of  various  kinds,  especially  machine  brushes 
for  polishing  linen  and  cotton  yarns,  and  for  brushing  velvets. 

f  The  true  panama  fibre  for  the  making  of  the  hats  that  go  by  that  name  is 
obtained  from  the  Planta  de  Torquilla  or  Carludovica  Palmata,  which  grows  wild 
in  the  swamps  of  tropical  America.  The  leaves  employed  for  the  making  of  the 
hats  are  the  young  ones,  which  are  plucked  before  they  have  fully  expanded. 
They  are  then  boiled  in  water  to  which  a  little  lemon  juice  has  been  added,  and 


THE  VEGETABLE  FIBRES  163 

(c)  Plaits  from  various  materials.     (Bast  and  thin  woods 
used  in  millinery  trimmings.) 

2.  Mats  and  mattings;    also  thatch  materials. 

(a)  Commercial  mattings  from  Eastern  countries.* 

(b)  Sleeping-mats,  screens,  etc. 

(c)  Thatch-roofs,    made    from    tree-basts,    palm-leaves, 
grasses,  etc. 

3.  Basketry. 

(a)  Manufactures  from  woody  fibre. 

(b)  From  whole  or  split  leaves  or  stems. 

4.  Miscellaneous  manufactures. 

Willow-ware  in  various  forms;    chair-bottoms,  etc.,  from 
splints  or  rushes. 

F.  VARIOUS  FORMS  OF  FILLING. 

1 .  Stuffing  or  Upholstery. 

(a)  Wadding,    batting,    etc.,    usually   commercially  pre- 
pared lint-cotton. 

(b)  Feather  substitutes  for  filling  cushions,  etc. ;  cotton, 
seed-hairs,  tomentum  from  surfaces  of  leaves,  other  soft  fibrous 
material. 

(c)  Mattress  and  furniture  filling;    the  tow  or  waste  of 
prepared  fibre;    unprepared  bast,  straw,  and  grasses;   Spanish 
moss,  etc. 

2.  Caulking. 

(a)  Filling    the    seams    in    vessels,    etc.;     oakum    from 
various  fibres. 

afterwards  they  are  hung  up  to  dry  in  an  airy  though  shady  place.  Throughout 
the  operations  of  drying  and  hat  plaiting  the  straw  should  never  be  exposed  to 
the  sun,  as  this  would  cause  the  hat  to  have  a  streaky  appearance  owing  to  the 
unequal  bleaching  of  the  strips.  When  the  leaves  are  nearly  dry  they  are  split 
into  very  narrow  strips  of  an  even  width,  and  are  then  tied  in  bunches  and  left 
to  dry.  After  the  plaiting  is  finished  the  hats  are  cleaned  with  soap  and  lemon 
juice,  polished,  and  are  then  ready  for  the  market. 

*  The  Japanese  floor  mattings  imported  into  this  country  are  made  either 
from  the  rush  known  as  Juncus  effusus  (the  Bingo-i  mat  rush),  or  from  the  Cyperus 
unilans  (the  Shichito-i  mat  rush),  the  better  quality  being  made  from  the  first- 
named  product.  The  Juncus  ejfusus  is  also  grown  on  the  Pacific  Coast  of  the 
United  States,  as  well  as  a  similar  species  known  as  /.  robustus. 


164  THE  TEXTILE  FIBRES 

(b)  Filling  the  seams  in  casks,  etc.;  leaves  of  reeds  and 
giant  grasses. 

3.  Stiffening. 

In  the  manufacture  of  "  staff  "  for  building  purposes, 
and  as  substitutes  for  cow-hair  in  plaster;  New  Zealand  flax; 
palmetto  fibre. 

4.  Packing. 

(a)  In  bulkheads,  etc.;  coir,  cellulose  of  corn-pith.     In 
machinery,  as  in  valves  of  steam-engines;    various  soft  fibres. 

(b)  For  protection  in  transportation;    various  fibres  and 
soft  grasses;   marine  weeds;    excelsior. 

G.  PAPER  MATERIAL. 

1.  Textile  papers. 

(a)  The  spinning  fibres  in  the  raw  state;    the  secondary 
qualities  or  waste  from  spinning-mills,  which  may  be  used  for 
paper-stock,  including  tow,  jute-butts,  Manila  rope,  etc. 

(b)  Cotton  or  flax  fibre  that  has  previously  been  spun> 
and  woven,  but  which,  as  rags,  finds  use  as  a  paper  material. 

2.  Bast  papers. 

This  includes  Japanese  papers  from  soft  basts,  such  as 
the  paper  mulberry. 

3.  Palm  papers. 

From  the  fibrous  material  of  palms  and  similar  plants. 
Palmetto  and  yucca  papers. 

4.  Bamboo  and  grass  papers. 

This  includes  all  paper  material  from  grass-like  plants, 
including  the  bamboos,  esparto,  etc. 

5.  Wood-pulp,  or  cellulose. 

The  wood  of  spruce,  poplar,  and  similar  "  paper-pulp  " 
woods  prepared  by  various  chemical  and  mechanical  processes. 

Wiesner  gives  the  following  botanical  classification  of 
the  more  important  vegetable  fibres: 

A.  VEGETABLE  HAIRS. 

1.  Cotton  (seed-hairs  of  Gossypium  sp.). 

2.  Bombax  cotton  (fruit-hairs  of  BombacecB). 


THE  VEGETABLE  FIBRES  165 

3.  Vegetable  silks  (seed-hairs  of  various  Asclepiadacea 

and  A  pocynacea) . 

B.  BAST  FIBRES  FROM  THE  STALKS  AND  STEMS  OF  DICOTYLE- 

DONOUS PLANTS. 

(a)  Flax-like  fibres. 

4.  Flax  (Linum  usitatissimum) . 

5.  Hemp  (Cannabis  saliva). 

6.  Gambo  hemp  (Hibiscus  cannabinus). 

7.  Sunn  hemp  (Crotalaria  juncea) . 

8.  Queensland  hemp  (Sida  retusa). 

9.  Yercum  fibre  (Calotropis  gigantea). 

(b)  Bcehmeria  fibres . 

10.  Ramie  or  China  grass  (Bcehmeria  nivea). 

(c)  Jute-like  fibres. 

11.  Jute  (Cor chorus  capsmaris  and  C.  olitorius). 

12.  Raibhenda  (Abelmoschus  telraphyllos). 

13.  Pseudo-jute  (Urena  sinuata). 

(d)  Coarse  bast  fibres. 

14.  Bast  fibres  from  Bauhinia  racemosa. 

15.  Bast  fibres  from  Thespesia  lampas. 

1 6.  Bast  fibres  from  Cordia  latifolia. 

(e)  Basts. 

17.  Linden  bast  (Tilia  sp.). 

1 8.  Bast  from  Sterculia  villosa. 

19.  Bast  from  Holoptelea  integrifolia. 

20.  Bast  from  Kydia  calycina. 

21.  Bast  from  Lasiosyphon  speciosus. 

22.  Bast  from  Sponia  Wightii. 

C.  VASCULAR  BUNDLES  FROM  MONOCOTYLEDONOUS  PLANTS. 

(a)  Leaf  fibres. 

23.  Manila  hemp  (Musa  lextilis  and  others  of  this  kind) 

24.  Pita  (Agave  americana  and  A.  mexicana). 

25.  Sisal  (Agave  rigida). 

26.  Mauritius  hemp  (Agave  fcetida). 

27.  New  Zealand  flax  (Phormium  tenax). 

28.  Aloe  fibres  (Aloe  sp.). 


166  THE  TEXTILE   FIBRES 

29.  Bromelia  fibres  (Bromelia  sp.). 

30.  Pandanus  fibres  (Pandanus  sp.). 

31.  Sansevieria  fibres  (Sansevieria  sp.). 

32.  Sparto  fibres  (Stipa  tenacissima) . 

33.  Piassave   (Attalea  funifera,  Raphia  vinifera,  etc.). 

(b)  Stem  fibres. 

34.  Tillandsia  fibres,  southern  moss  (Tillandsia  usneoides). 

(c)  Fruit  fibres. 

35.  Coir  or  cocoanut  fibre  (Cocos  nucifera). 

36.  Peat  fibres. 

(d)  Paper  fibres. 

37.  Straw  fibres  (rye,  wheat,  oat,  rice). 

38.  Esparto  fibres  (leaf  fibres  of  Stipa  tenacissima). 

39.  Bamboo  fibres  (Bambusa  sp.). 

40.  Wood  fibre  (pine,  fir,  aspen,  etc.). 

41.  Bast  fibre  from  paper  mulberry  (Broussonetia  papy- 

r  if  era) . 

42.  Bast  fibre  from  Edgeworthia  papyri/era. 

43.  Peat  fibres. 

Lecomte  (Textiles  vegetaux)  gives  the  following  classification 
with  reference  to  the  botany  of  the  textile  fibres. 

A.  VEGETABLE  HAIRS. 
Cotton. 

Asclepias.     ) 

* .    S'    \  Minor  vegetable  hair  fibres. 
Epilobium. 

Typha,  etc.  j 

B.  BAST  FIBRES. 

I.  Dicotyledons. 

a.  Urticacecz  family. 

Hemp  (Cannabis). 

Ramie  (Boehmeria). 

Nettle  (Urtica). 

Paper  mulberry  (Broussonetia). 

Hop  (Humulus). 


THE  VEGETABLE  FIBRES  167 

b.  Linacece  family. 

Linen  (Linum). 

c.  Thymeleacea  family. 

Lace  bark  (Lagetta). 
Nepal  paper  (Daphne). 

d.  TiliacecE  family. 

Jute  (Cor chorus). 
Linden  (Tilia). 

e.  Malvacecz  family. 

Queensland  hemp  (Sida). 
Caesar  weed  (Urena). 
Pseudo-hemps  (Hibiscus). 

f.  Papilionacea  family. 

Sunn  hemp  (Crotalaria) . 
Clover  (Melilotus). 
Ginestra  (Genista). 
Spanish  sparto  (Spartium). 

g.  Cordiacece  family. 

Cordia  fibres. 
h.  AsclepiadacecE  family. 

Giant  asclepias  (Calotropis). 

II.  Monocotyledons. 

a.  Graminea  family. 

Sparto  grass  (Stipa). 
Weeping  sylvan  (Lygeuni). 

b.  Liliacece  family. 

New  Zealand  hemp  (Phormium). 

Yucca  (Yucca  sp.). 

Bowstring  hemps  (Sansemeria). 

c.  Amaryllidacece  family. 

Sisal  hemps  (Agave). 

d.  Bromeliacea  family. 

Pineapple  (Ananas). 
Bromelia  fibres  (Bromelia). 

e.  Musacece  family. 

Manila  hemp  (Musa) 


168  THE  TEXTILE  FIBRES 

/.  Naiadacea  family. 

Sea-wrack  (Zostera). 
g.  PalmcB  family. 

Coir  (Cocos). 
Raffia  (Raphia). 

Murumuru  palm  (Astrocaryum). 
Crin  vegetal  (Chamcerops) . 
Rattan  cane  (Calamus). 
Sago-palm  (Arenga). 
Date-palm  (Phoenix). 
Talipot  palm  (Corypha). 
Oil-palm  (Elais). 

3.  Physical  Structure. — (a)  Seed-hairs,  or  plumose  fibres, 
are  divided  into  three  morphological  classes: 

(1)  Those  consisting  of  single  cells,  one  end  of  which  is 
closed  and  tapers  to  a  point,  the  other  end  being  broken  off 
abruptly  where  it  is  torn  from  the  seed  to  which  it  was  fastened 
during  growth.     This  class  includes  the  most  important  plumose 
fibres,  such  as  cotton  and  the  vegetable  silks. 

(2)  Those  consisting  of  a  series  of  cells  joined  together  to 
form  a  continuous  fibre;    this  class  includes  the  tomentum  or 
epidermal  hair  obtained  from  certain  ferns;  these  are  practically 
valueless  as  textile  materials,  though  employed  for  upholstery 
and  similar  uses. 

(3)  Those  consisting  of  several  series  of  cells,  represented 
by  the  fibres  of  the  so-called  cotton-grass  and  elephant-grass. 

The  hair  fibres  may  originate  on  almost  any  organ  of  the 
plant  exposed  to  the  air.  The  following  table  indicates  the 
origin  of  the  majority  of  such  fibres.* 

Hair  Fibres. 
(i)  Covering  the  seeds,  either  entirely  or  in  part: 

Cotton Malvacea. 

Marsdenia 

Calotropis 

A    j     .  AsclepidecB. 

Asclepias 

Vincetoxicum  J 

*  See  Lecomte,  Textiles  vegetaux. 


THE  VEGETABLE  FIBRES  169 

Beaumontia 
Strophantus 
Epilobium .  .  .  (Enotheracea. 

(2)  Contained  in  the  flower  (rudimentary  floral  envelope): 
Typha Typhacea. 

Eriophorum.  .  .Cyperacece. 

(3)  Lining  the  interior  of  the  fruit: 
Ochroma ...     1 

Bombax. .  .    .   [  Bombacea. 
Eriodendron    J 

(4)  Covering  stalks  and  leaves: 
Cibotium Ferns. 

The  cell-wall  of  the  plumose  fibres  in  some  cases  is  relatively 
thin,  while  in  others  it  is  comparatively  thick.  It  is  generally 
without  apparent  structure,  though  sometimes  it  is  seen  to 
contain  pores,  and  occasionally  a  mesh-like  interlacing  of  fila- 
ments is  observable,  especially  at  the  base  of  the  fibre.  The 
inner  surface  of  the  cell-wall  is  usually  coated  with  a  cuticle 
of  dried  protoplasm,  which  is  evidently  similar  in  constitution 
to  the  outer  cuticle,  as  it  also  remains  undissolved  when  the 
fibre  is  dissolved  in  either  concentrated  sulphuric  acid  or  an 
ammoniacal  solution  of  copper  oxide.  Lecomte  *  gives  the 
following  classification  of  vegetable  fibres  with  respect  to  their 
cellular  structure: 

1 .  Fibres  consisting  of  a  single  isolated  cell : 

Hairs.  Fibres. 

Cotton.  Cottonized  ramie. 

Asdepias  silk. 
Bombax  cotton. 

2.  Single  fibres  associated  in  bundles: 
Unbleached  jute. 

Linen  (poorly  prepared  linen  frequently  contains  paren- 

chymous  cells  and  epidermal  cells.) 
Ambari  hemp  (Hibiscus). 
Ramie. 
Hemp  (well  prepared). 

*  Textiles  vegetaux. 


170  THE  TEXTILE  FIBRES 

3.  Fibres  with  medullary  cells: 
Queensland  hemp  (Sida  retusa). 
Cor  did  latifolia. 

Thespesia  lampas. 

4.  Fibres  with  parenchymous  cells: 
Abelmoschus  tetraphyllos. 
Urena  sinuata. 

Sunn  hemp  (Crotalaria  juncea). 
Calotropis  gigantea. 
Hemp  (as  often  prepared). 

(b)  Bast  Fibres. — The  general  term  of  bast  fibre  includes 
really  two  distinct  forms;  if  the  fibre  occurs  in  the  bast  itself 
it  should  be  designated  as  true  bast  fibre,  such  as  linen,  hemp, 
and  jute.  When,  however,  the  fibres  do  not  occur  in  the  bast, 
but  in  single  bundles  in  the  leaf  structure  of  the  plant,  they  should 
be  designated  as  sclerenchymous  fibres.  In  true  bast  fibres 
there  are  seldom  to  be  noticed  distinct  pores,  whereas  the 
sclerenchymous  fibres  are  abundantly  supplied  with  them. 
On  the  other  hand,  however,  the  true  bast  fibres  frequently 
show  peculiar  dislocations  or  joints  caused  by  an  unequal  cell 
pressure  in  the  growing  plant;  these  are  entirely  absent  in  the 
sclerenchymous  fibres.  The  ends  of  all  bast  fibres  are  usually 
quite  characteristic  and  exhibit  a  wide  diversity  of  -forms; 
at  times  they  are  sharp-pointed  and  again  blunt;  some  possess 
but  a  single  point,  while  others  are  split  or  forked;  sometimes 
the  cell- wall  is  thicker  than  in  the  rest  of  the  fibre,  and  some- 
times it  is  thinner.  When  the  cells  occur  in  bundles  they  are 
frequently  separated  from  one  another  by  a  so-called  median 
layer,  which  forms  a  sort  of  matrix  in  which  the  separate  filaments 
are  imbedded.  This  layer  usually  differs  in  its  chemical  com- 
position from  the  cell-wall  proper,  and  gives  different  color 
reactions  with  various  reagents,  as  it  generally  consists  of 
lignified  tissue.  In  many  cases  the  cell-walls  appear  to  have 
a  distinct  structure,  being  composed  of  concentric  layers  which 
in  cross-section  exhibit  a  stratified  appearance. 

The  bast  fibres  may  be  roughly  divided  into  four  classes 


THE  VEGETABLE  FIBRES  171 

with  reference  to  the  comparative  sizes  of  the  cell-wall  and  the 
inner  canal  or  lumen: 

(1)  The  canal    takes  up  about    four-fifths  of    the  diameter 
of  the  fibre: 

Ramie  and  china-grass. 

(2)  The  canal  is  about  two-thirds  of  the  diameter  of  the 
fibre: 

Pineapple  fibre. 

Hemp. 

Pita  and  sunn  hemp. 

(3)  The  canal  is  mostly  less  than  one-half  the  diameter  of 
the  fibre. 

Ambari  hemp  (Hibiscus), 

Yucca, 

New  Zealand  hemp  (Phormium  tenax), 

Manila  hemp. 

(4)  The  canal  is  often  reduced  to  a  mere  line : 
Linen. 

The  inner  canal  is  very  regular  (and  consequently  the  cell- 
wall  will  be  of  uniform  thickness)  in  fibres  of  yucca,  New  Zea- 
land hemp,  sunn  hemp,  pita  hemp,  linen,  ramie,  and  the  plumose 
fibres.  On  the  other  hand,  the  canal  is  irregular  (with  resulting 
irregularities  in  the  thickness  of  the  cell- wall)  in  fibres  of  jute, 
coir,  Urena  sinuata,  Abelmoschus,  etc. 

All  plant-cell  membranes  are  doubly  refractive  towards 
light,  and  this  is  especially  true  of  thick-walled  cells  which  are 
parallel  to  the  fibre  proper.  If  such  a  fibre  is  examined  in  the 
dark  field  of  a  micro-polariscope  it  shows  a  beautiful  arrange- 
ment of  bright  prismatic  colors. 

The  degree  of  double  refraction  varies  with  different  fibres; 
in  some,  as  for  example  in  coir,  it  is  very  weak,  while  in  others, 
such  as  linen  and  hemp,  it  is  very  strong.  The  following  table 
gives  the  polarization  colors  shown  by  various  fibres: 

Fibre.  Polarization  Colors. 

Vascular  and  parenchy- 


mous  cells  of  wood 
and  straw.  . 


Dark  gray. 


172  THE  TEXTILE  FIBRES 

Epidermal  cells  of  straw  1  _ 

and  esparto park  gray. 

Coir Dark  gray. 

Cotton  {Dark   gray    to   light  gray;    also 

|         white  to  yellow. 

New  Zealand  flax Ditto. 

Fibre  cells  of  jute  and      JDark  gray  to  light    gray;    yel- 
esparto {        lowish  to  red. 

Bast  cells  of  flax  and        { White;    yellowish,     orange,    red, 
he  violet,  changing  to  yellowish 

white  and  violet. 

4.  Physical  Properties,  (a)  Color.— The  vegetable  fibres 
in  the  raw  state  vary  considerably  in  color;  some,  like  cotton, 
ramie,  and  the  vegetable  silks,  are  almost  pure  white.  Others, 
like  linen,  possess  a  grayish  brown  color;  while  still  others, 
like  jute  and  hemp,  have  a  decided  brown  color.  These  colors, 
however,  are  due  to  incrusting  impurities,  as  the  cellulose 
fibres,  purified  and  freed  from  all  such  foreign  matters,  are 
always  white. 

(b)  Lustre. — The  vegetable  fibres  are  usually  less  lustrous 
than  those  of  animal  origin,  and  especially  silk,  though  they 
differ  much  in  this  respect.     Cotton  probably  has  the  least 
lustre  of  any,  as  its  surface  is  by  no  means  smooth  and  even, 
but  presents  a  wrinkled  and  creased  appearance,  hence  scatters 
the  rays  of  light  reflected  therefrom.     Other  plumose  fibres,  such 
as  the  various  vegetable  silks,  have  a  very  smooth  surface,  and 
consequently  exhibit   considerable   lustre.     Linen,  jute,  ramie, 
and  the  bast  fibres  in  general,  when  separated  into  their  fine 
filaments  and  properly  freed  from  all  incrusting  matter,  possess 
a  rather  high  degree  of  lustre;    for  though  they  have  more  or 
less  roughened  places  and  irregularities  on  their  surface,  the 
major  portion  of  such  surface  is  smooth  and  regular. 

(c)  Elasticity. —  The  more  closely  the  fibre  approximates 
")  pure  cellulose  the  greater  becomes  its  flexibility  and  elasticity, 

and  the  more  it  is  lignified,  that  is  to  say,  the  more  it  is  changed 
into  woody  tissue,  the  less  these  qualities  become.     That  is 


THE  VEGETABLE   FIBRES 


173 


to  say,  the  highly  lignified  fibres  are  stiff  and  brittle  and  but 
little  adapted  to  the  spinning  of  fine  yarns. 

(d)  Tensile  Strength. — In  tensile  strength  the  vegetable 
fibres  vary  considerably;  owing  to  the  great  difference  in  the 
physical  form  and  thickness  of  the  various  fibres,  it  is  difficult 
to  give  a  comparison  of  their  respective  strengths.  The  fol- 
lowing table  gives  a  comparison  between  the  more  important 
fibres : 


Fibre. 

Breaking 
Length  in 
Kilometres. 

Tensile  Strength, 
Kilograms  per 
Sq.  Millimetre. 

Cotton  

23  .O 

34-  27 

Linen                         

24.0 

36.00 

Tute 

•2A      C 

40    ^1 

Hemp 

^2    O 

78  oo 

Coir                         

17.8 

JManila  hemp 

31  8 

China-grass 

20  o 

Raw  silk                 

30.8 

4O       O4 

(e)  Hygroscopic  Properties. — The  hygroscopic  moisture  con- 
tained in  vegetable  fibres  is  considerably  lower  than  that  present 
in  either  wool  or  silk.  While  the  latter  fibres  under  normal 
atmospheric  conditions  will  average  as  much  as  12  to  16  per 
cent  of  moisture,  cotton  and  linen  will  have  only  from  6  to  8 
per  cent.  The  table  on  page  174  (after  Wiesner)  gives  the 
amount  of  moisture-  in  various  vegetable  fibres  in  the  ordinary 
air-dry  condition,  and  also  the  greatest  amount  they  will  absorb 
hygroscopically.* 

*  According  to  Scheurer  (Bull.  Soc.  Ind.  Mulhouse,  1900,  p.  89)  each  kind  of 
fibre  possesses  a  definite  capacity  of  absorption  when  exposed  to  the  action  of 
steam  under  constant  conditions.  When  equilibrium  had  become  established  he 
obtained  the  following  results: 

Fibre.  Percentage  Moisture. 

Cotton 23 .  o 

Raw  linen : 27.7 

Raw  jute 28 . 4 

Bleached  silk ...36.5 

Bleached  and  mordanted  wool .   50 .  o 


174 


THE  TEXTILE   FIBRES 

HYGROSCOPIC  MOISTURE  IN  VEGETABLE  FIBRES. 


Fibre. 


Air-dry 
Condition. 


Maximum 

Amount 

Hygroscopic 

Water. 


Cotton ". 6 . 66 

Flax  (Belgian) 5 .  70 

Jute 6 .  oo 

China-grass 6.52 

Manila  hemp 1 2 . 50 

Sunn  hemp 5.31 

Hibiscus  cannabinus 7-38 

Abelmoschus  tetraphyllos 6 . 80 

Esparto 6.95 

Urena  sinuata 7.02 

Piassave  * 9.26 

Sida  retusa 7 . 49 

Aloe  perfoliata 6 . 95 

Bromelia  karatas 6.82 

Thespesia  lampas 10 . 83 

Cordia  lalifolia .* 8 . 93 

Bauhinia  racemosa  f 7-84 

Tillandsia  fibre 9 .  oo 

Pita 1 2 . 30 

C'alotropis  gigantea  (bast) 5 . 67 


20.99 
13.90 
23-30 
18.15 
50.00 
10.87 
14.61 
13.00 
13-32 
1 5  20 

16.98 
17.11 
18.03 
18.19 
18.19 

18.22 
19.  12 
2O  50 
30.OO 


5.  Chemical  Composition  and  Properties. — Although  cellulose 
forms  the  chief  constituent  of  all  vegetable  fibres,  it  varies 
much  in  its  purity  and  associated  products  in  its  occurrence  in 
the  various  fibres.  {  Seed-hairs,  like  cotton,  consist  almost 

*  Piassave  fibre  is  obtained  from  a  palm-tree,  Atlalea  funifera.  It  is  a 
structural  fibre  obtained  from  the  dilated  base  of  the  leaf-stalks.  It  is  stiff, 
wiry,  and  bright  chocolate  in  color,  and  is  principally  used  in  the  manufacture 
of  brushes.  It  is  also  used  on  the  street-sweeping  machines  in  London.  The 
palm  grows  principally  in  Brazil,  where  the  natives  use  the  fibre  for  making 
coarse  cables  which  are  very  durable  and  so  light  that  they  will  float  on 
water. 

f  The  Bauhinia  is  a  genus  of  arborescent  or  climbing  plants  found  in  trop- 
ical countries.  The  fibre  is  obtained  from  the  bast  of  the  inner  bark,  and  may 
be  made  into  coarse  cordage,  but  it  soon  rots  in  water.  The  fibre  is  reddish  in 
in  color  and  tough  and  strong,  and  has  been  employed  in  India  for  construction 
of  bridges. 

|  In  their  chemical  composition  vegetable  fibres  consist  of  three  parts,  cell 
tissue  (cellulose),  woody  tissue  (lignin),  and  cork  tissue  (cutose).  The  first  is 


THE  VEGETABLE  FIBRES  175 

entirely  of  cellulose  in  a  rather  pure  state,  but  the  bast  and 
vascular  fibres  always  contain  more  or  less  alteration  products 
of  cellulose,  chief  among  which  is  ligno-cellulose,  or  lignin; 
in  fact  jute  is  almost  entirely  composed  of  this  latter  substance. 
Seed-hairs  mostly  consist  of  one  single  cell  to  the  individual 
fibre  and  have  very  little  foreign  or  incrusting  material  present. 
The  other  fibres  are  made  up  of  an  aggregation  of  cells  bound 
together  in  a  compact  form,  and  in  the  cell  interstices,  there  is 
always  present  more  or  less  gummy  and  resinous  matter,  oils, 
mineral  matter,  and  lignified  tissue.  All  vegetable  fibres 
appear  to  contain  more  or  less  pigment  matter,  usually  of  a 
slight  yellowish  or  brownish  color.  In  ordinary  cotton  and 
ramie  this  coloring  matter  occurs  in  only  a  very  small  amount 
and  the  natural  fibre  is  quite  white  in  appearance.  There  are 
some  varieties  of  cotton,  however,  which  are  distinctly  brown 
in  color.  Flax,  jute,  hemp,  etc.,  contain  a  considerable  amount 
of  pigment  and  are  of  a  more  or  less  pronounced  brownish  color. 
Besides  cellulose  and  lignin,  there  is  also  present,  especially 
in  seed-hairs,  a  cutose  membrane  (cork  tissue)  in  the  form  of  an 
external  cuticle.  Cutose  is  insoluble  in  concentrated  sulphuric 
acid,  but  is  slightly  soluble  in  boiling  caustic  potash.  It  doubt- 

the  basic  ingredient  of  all  plant  membranes.     The  following  are  the  distinguishing 
reactions  of  these  three  tissues: 

1.  Pure  cell  tissue  is  recognized  by  giving  blue  colorations  with  chlor-iodide 
of  zinc  and  iodin-sulphuric  acid  reagent.     It  is  soluble  in  ammoniacal  copper 
oxide  and  in  concentrated  sulphuric  acid  without  a  brown  coloration. 

2.  Woody  tissue  gives  a  yellow  coloration  with  chlor-iodide  of  zinc  and  also 
with  anilin  sulphate,  while  with  phloroglucin  reagent  it  gives  a  red  coloration. 
It  is  soluble  in  concentrated  sulphuric  acid  with  a  strong  brown  coloration,  but 
is  insoluble  in  ammoniacal  copper  oxide  solution. 

3.  Cork  tissue  also  gives  a  yellow  coloration  with  chlor-iodide  of  zinc,  but 
beyond  this  shows  no  especially  characteristic  reaction.     It  is  insoluble  in  both 
ammoniacal   copper   oxide   and   concentrated   sulphuric   acid.     It   is   somewhat 
soluble,  however,  in  boiling  caustic  potash  solution. 

Both  the  woody  tissue  and  the  cork  tissue  may  be  removed  from  the  cell 
membrane  proper  by  treatment  with  suitable  chemical  reagents,  without  destroy- 
ing the  form  of  the  fibrous  elements.  Boiling  with  Schulye's  reagent  (nitric 
acid  and  potassium  chlorate)  will  cause  the  decomposition  of  vegetable  membranes 
into  their  fibre  elements  while  still  preserving  the  original  form  of  the  fibre.  The 
same  decomposition  occurs  in  the  technical  preparation  of  wood-pulp,  where 
the  wood  is  boiled  with  dilute  alkali  or  sulphurous  acid  under  high  pressure. 


176  THE  TEXTILE  FIBRES 

less  originates  from  the  plant-wax  which  is  imbedded  in  the 
cell.  Albuminous  matter  also  occurs  in  the  fibre  elements, 
mostly  as  a  dried  tissue  which  fills  the  lumen  of  the  fibre  more 
or  less  completely.  It  also  occurs  as  a  thin  film  which  coats 
the  inner  wall  of  the  cell  and  remains  undissolved  when  the 
fibre  is  treated  with  concentrated  sulphuric  acid.  This  mem- 
brane exhibits  all  the  reactions  of  albumin.  Silicic  acid  some- 
times is  present  in  vegetable  fibres,  but  only  in  the  walls  of  the 
stegmata  *  and  in  epidermal  cells.  On  ignition  the  siiicious 
matter  is  left  in  almost  its  original  form.  The  siiicious  skeleton 
is  insoluble  in  hydrochloric  acid,  whereas  the  rest  of  the  ash  is 
readily  dissolved  by  this  reagent.  Crystals  of  calcium  oxalate 
occasionally  occur  in  some  fibres;  they  are  insoluble  in  acetic 
but  dissolve  in  hydrochloric  acid.  On  ignition  of  the  fibres 
these  crystals  are  converted  into  calcium  carbonate  without 
much  change  of  form,  and  then  are  soluble  in  even  very  dilute 
acids. 

Woody  fibre  is  to  be  found  in  many  vegetable  fibres,  and  its 
presence  always  lowers  the  economic  value  of  the  fibre.  The 
presence  of  woody  fibre  may  readily  be  determined  by  the 
application  of  a  number  of  characteristic  chemical  tests.  Anilin 
sulphate,  for  instance,  with  woody  fibre  gives  a  golden  yellow 
color;  phloroglucin  with  hydrochloric  acid  gives  a  red  color, 
phenol  with  hydrochloric  acid  a  green  color,  as  does  also  indol 
with  hydrochloric  acid,  and  a  solution  of  chlor-iodide  of  zinc 
gives  a  brownish  yellow  color.  Woody  fibre  is  also  destroyed 
by  the  action  of  alkalies  and  hypochlorites  in  the  bleaching 
process;  and  in  fact  this  process  usually  has  for  its  chief  object 
the  decomposition  and  removal  of  the  woody  fibre  which  may 

*  Many  fibres  derived  from  monocotyledonous  plants  exhibit  under  the  micro- 
scope characteristic  fragments  of  mineral  matter  known  as  stegmata.  These  are 
generally  crystalline  in  structure  and  consist  of  calcium  oxalate,  although  amor- 
phous particles  of  siiicious  matter  are  also  to  be  noticed  at  times.  These  siiicious 
particles  often  occur  in  the  form  of  a  string  of  beads,  a  form  which  persists  even 
after  the  fibre  has  been  reduced  to  an  ash  by  ignition.  The  siiicious  skeletons 
may  also  be  observed  when  the  cellulose  of  the  fibre  has  been  destroyed  by  treat- 
ment with  chromic  acid.  Stegmata  are  especially  to  be  observed  in  coir  (cocoa- 
nut  fibre),  Manila  hemp,  and  piassava  fibre. 


THE  VEGETABLE  FIBRES  177 

be  present.  Due  to  this  fact,  certain  bleached  fibres,  such  as 
jute  and  hemp,  may  no  longer  exhibit  the  above-mentioned 
color  reactions,  although  they  may  have  done  so  originally 
in  the  raw  condition. 

There  are  several  reagents  which  are  serviceable  in  micro- 
chemical  tests  on  vegetable  fibres,  as  they  yield  distinctive 
color  reactions.  With  the  iodin-sulphuric  acid  reagent  *  the 
principal  fibres  give  the  following  reactions. 

(a)  Blue  colors: 
Cotton. 

Raw  fibre  from  Hibiscus  cannabinus. 

Calotropis    gigantea    (greenish    blue    to 

blue). 

"     flax'fibre. 
Cottonized  ramie. 

Raw  sunn  hemp  (often  copper-red). 
11     hemp  (greenish  blue  to  pure  blue). 

(b)  Yellow  to  brown  colors: 
Bombax  cotton. 

Vegetable  silk  (occasionally  greenish  or  greenish  blue). 
Raw  jute. 

"       fibre  of  Abelmoschus  letraphyllos. 
Urena  sinuata. 

Bauhinia  racemosa  (blackish  brown). 
Thespesia  lampas. 
"     esparto  (reddish  brown). 

aloe   (mostly  reddish  brown,   sometimes  greenish 

and  even  blue). 

New  Zealand  flax  (yellow,  green  to  blue,  depending  on 
the  purification  of  the  fibre). 

6.  Lignin. — The  fibres  in  the  second  class  have  their  cellu- 
lose largely  contaminated  with  lignin,  and  hence  have  somewhat 
of  the  character  of  woody  tissue.  It  is  to  be  remarked,  how- 
ever, that  by  treatment  with  nitric  acid  (or  by  boiling  with 
caustic  potash  under  pressure)  these  fibres  lose  most  of  the 

*  For  the  preparation  of  this  reagent  see  p.  465. 


178  THE  TEXTILE  FIBRES 

lignin  which  encrusts  their  tissues,  and  then  exhibit  the  char- 
acteristics of  ordinary  cellulose;  that  is  to  say,  they  dissolve 
in  Schweitzer's  reagent,  and  are  colored  blue  with  the  iodin- 
sulphuric  acid  reagent. 

Ammoniacal  copper  oxide  *  (Schweitzer's  reagent)  is  a  re- 
agent which  gives  characteristic  reactions  with  many  vegetable 
fibres,  as  follows: 

(a)  The  fibres  are  almost  completely  dissolved:] 
Cotton. 

Cottonized  ramie. 

Raw  fibre  of  Hibiscus  cannabinus. 

1 1      Calotropis  gigantea. 
11     flax. 

' '     hemp  (only  the  bast  cells  dissolve,  the  accompany- 
ing parenchymous  cells  remain  undissolved). 
1 1     sunn  hemp. 

(b)  The  fibre  becomes  blue  in  color  and  is  more  or  less  swollen: 
Raw  jute. 

ft     fibre  of  Abelmoschus  tetraphyllos. 

Urena  sinuata. 
' '  Bauhinia  racemosa. 

Thespesia  lampas. 
' '     New  Zealand  flax. 
"     fibre  of  Aloe  perfoliata  (slightly  swollen). 

Bromelia  karatas  (strongly  swollen). 

Sida  retusa  (becomes  greenish  at  first,  then 
blue  and  swells  up). 

(c)  The  fibre  is  colored  without  swelling: 
Vegetable  silk  (blue). 

Bombax  cotton  (blue). 
Raw  esparto  (bright  green). 
' '     fibre  of  Cordia  latifolia  (blue) . 
Sterculia  villosa  (blue). 

*  For  the  preparation  of  this  reagent  see  p.  269. 

f  With  the  exception  of  the  external  cuticle,  the  inner  cell- wall,  and  dry  proto- 
plasmic residue.  For  the  morphological  alterations  which  the  fibres  undergo 
by  treatment  with  this  reagent  see  under  the  description  of  the  separate  fibres. 


I 
THE  VEGETABLE  FIBRES  179 

A  solution  of  anilin  sulphate  may  be  used  to  detect  lignifica- 
tion  in  a  fibre;  this  reagent  gives  the  following  color  reactions: 

(a)  The  color  of  the  fibre  is  not  changed  or  but  slightly: 
Cotton. 

Bombax  cotton  (very  slight  coloration). 
Cottonized  ramie,  also  the  bast  cells  of  raw  ramie. 
Raw  flax. 

"     bast   fibres   of   Hibiscus    cannabinus    (very   slight 
coloration) . 

' '     bast  fibres  of  Calotropis  gigantea  (very  slight  colora- 
tion). 

' '     sunn  hemp. 

"     New  Zealand  flax  (very  slight  coloration). 
Manila  hemp  (very  slight  coloration). 

(b)  The  fibre  is  distinctly  or  very  strongly  colored: 
Vegetable  silk  (intense  citron-yellow). 
Raw  jute  (golden  yellow  to  orange). 

' '     bast  fibres  of  A  belmoschus  tetraphyllos  (golden  yel- 
low). 

Urena  sinuata  (golden  yellow). 
"        "        "  Sida  retusa  (yellow). 

"     bast  fibre  of  Thespesia  lampas  (golden  yellow). 

Cor dia  lati folia  (dull  yellow). 
fi     hemp  (pale  yellow). 
' '      esparto  (sulphur  yellow) . 
' '     fibre  of  Bromeliakaratas  (golden  yellow) . 

A  method  for  the  estimation  of  the  amount  of  lignin  in  fibres 
is  given  by  Herzog  *.  It  is  based  on  a  determination  of  the 
methyl  value,  that  for  pure  lignin  being  taken  as  52.9.! 

*  Chemiker  Zeitung,  vol.  20,  p.  461. 

f  When  a  substance  containing  a  methoxyl  group  is  heated  with  hydriodic 
acid,  methyl  iodide  is  formed,  and  the  so-called  "methyl  value"  refers  to  the 
amount  of  methyl  iodide  thus  formed.  The  determination  is  carried  out  as 
follows:  The  fibrous  material  is  finely  divided  and  from  0.2  to  0.3  gram  is  heated 
with  10  c.c.  of  hydriodic  acid  (sp.gr.  1.70)  in  a  flask  on  a  glycerin  bath,  while  a 
current  of  carbon  dioxide  gas  is  passed  through  the  flask.  The  vapors  produced 
are  passed  through  a  three-bulb  condenser,  the  first  bulb  being  empty  to  condense 


180 


THE  TEXTILE  FIBRES 


The  following  table  gives  the  methyl  value  and   correspond- 
ing amount  of  lignin  in  the  different  fibres: 


Fibre. 

Water, 
Per  Cent. 

Methyl  Value 
on  Fibre 
Dried  at 
100°  C. 

Lignin, 
Per  Cent. 

Bombax  cotton 

6   77 

6  87 

I  2    OO 

Vegetable  silk  (Calotropis  gigantea)  

6.88 

8.18 

I  ^    46 

Manila  hemp      .          

6.81 

I  c   02 

•3Q      I  I 

Pita 

7  10 

8   47 

16  02 

Aloe  

7  -9° 

Q    II 

1732 

Coir                                       

7  36 

22    OO 

41     ^O 

Tillandsia 

8  10 

ii   18 

21    1  3 

Nettle                 

8.15 

Ramie 

7  84 

O    77 

I    46 

Fibre  of  Morus  papyri/era  

6.08 

2  .  "?O 

4    74 

Linen  Russian                         

8  40 

4  81 

O    Qt 

'  '       Courtrai 

8  71 

Hemp,  Italian                

7  -03 

2    80 

r    32 

"       Polish      " 

8    20 

2    87 

*   46 

Jute.  . 

8.06 

21  .  2O 

4O       26 

7.  Chemical  Investigation  of  Vegetable  Fibres. — A  chemical 
study  of  the  fibres  involves  an  examination  of  their  chemical 
constituents.  As  previously  stated,  though  cellulose  is  the  prin- 
cipal chemical  compound  to  be  found  in  vegetable  fibres,  yet 
there  are  certain  other  substances  present,  which  at  times  may 
be  characteristic  of  the  fibre.  Then,  again,  the  cellulose 
which  occurs  in  different  classes  of  fibres  appears  to  be  some- 
what different  in  its  chemical  properties,  which  has  led  to  the 
supposition  of  different  forms  of  cellulose,  already  spoken  of  as 
ligno-cellulose,  pecto-cellulose,  etc.  Though  the  chemistry 
of  these  bodies  has  been  somewhat  studied  with  reference  to 
vegetable  fibres  by  Cross  and  Bevan  and  a  few  others,  yet  the 

the  steam,  the  second  containing  water  to  absorb  the  hydriodic  acid,  and  the 
third  containing  red  phosphorous  to  retain  any  iodin  liberated  by  the  decompo- 
sition of  the  hydriodic  acid.  The  vapors  of  methyl  iodide  (mixed  with  carbon 
dioxide)  issuing  from  the  bulbs  are  passed  into  a  flask  containing  a  mixture  of 
5  c.c.  of  a  40  per  cent  solution  of  silver  nitrate  with  50  c.c.  of  95  per  cent  alcohol. 
The  methyl  iodide  is  precipitated  as  silver  iodide,  which  is  weighed  in  the 
usual  manner;  100  parts  of  silver  iodide  are  equivalent  to  6.4  parts  of  methyl. 


THE  VEGETABLE  FIBRES  181 

subject  is  still  in  a  very  crude  condition,  and  there  is  much  to 
be  learned  in  this  field  of  chemical  research.  The  methods 
for  the  chemical  study  of  the  vegetable  fibres  adopted  by  Cross, 
and  continued  by  other  chemists,  may  be  stated  in  the  following 
form:  A  separate  portion  of  the  fibre  under  examination  is 
taken  for  each  determination,  and  the  results  are  calculated 
into  percentages  on  the  dry  weight  of  the  substance. 

(1)  Moisture. — This  may  be  called    hygroscopic    water    or 
water  of  condition;   it  is  obtained  by  drying  a  weighed  portion 
of  the  fibre  at  110°  C.  to  constant  weight.     If  dried  at  100°  C., 
about  i  per  cent  of  the  water  will  be  retained.     The  percentage 
of  hygroscopic   moisture   in   the   vegetable  fibres  varies   con- 
siderably with  the  different  state  of  humidity  of  the  surrounding 
air,  on  which  account  it  is  recommended  that  the  results  of  the 
analyses  should  be  expressed  on  the  dry  weight  of  the  fibre. 
It  is  interesting   to  note   that    the   contents  of    hygroscopic 
moisture  in  a  fibre  appears  to  be  an  index  of  the  susceptibility 
of  attack  by  hydrolytic  agents,  and  that  the  highest  class  of 
fibres  is  distinguished  by  its  relatively  low  amount  of  moisture. 

(2)  Ash. — This  is  taken  as  the  total  residue  left  after  igni- 
tion  of   the  fibre,   and   represents   the   mineral   constituents.* 
The  proportion  of  these  is  low  in  the  ligno-celluloses  and  higher 
in  the  pecto-celluloses,  especially  when  the  proportion  of  non- 
cellulose  is  high.     Admixture  of  non-fibrous  tissue  will  also  raise 
the  amount  of  ash,  as  this  tissue  contains  a  higher  proportion 
of  mineral  constituents. 

(3)  Hydrolysis. — This  refers  to  the  loss  of  weight  sustained 
by  the  fibre  (a)  on  boiling  for  five  minutes  with  a  i  per  cent 
solution  of  caustic  soda,  and  (b)  further  loss  of  weight  on  con- 
tinuing to  boil  for  one  hour.     The  first  loss  in  weight  represents 
the  proportion  of  fibre  soluble  in  the  alkali,  the  second  represents 
the  proportion  of  the  fibre  decomposed  by  actual  hydrolysis. 

*  The  natural  ash  of  vegetable  fibres  varies  from  0.5  to  2  per  cent,  and  usually 
the  major  portion  of  this  consists  of  silica.  The  exact  function  of  this  silicious 
matter  in  the  plant  cell  is  not  known;  according  to  Ladenburg  (Berichte,  1872, 
p.  568)  and  Dange  (Berichte,  1884,  p.  822)  the  silica  does  not  have  any  structural 
function  in  the  cell. 


182  THE  TEXTILE   FIBRES 

The  pecto-celluloses  are  often  so  resolved  by  the  action  of  the 
dilute  alkali  that  most  of  the  non-cellulose  is  dissolved  away. 
The  amount  of  hydrolysis  of  a  fibre  represents  in  some  measure 
the  power  of  resistance  of  a  fibre  to  the  action  of  the  boiling-out 
and  bleaching  processes,  as  well  as  the  power  of  resistance  to 
actual  wear  as  caused  by  frequent  washings  with  alkalies, 
soaps,  etc. 

(4)  Cellulose. — The  determination  of  the  value   and   com- 
position of  the  cellulose  is  made  as  follows:    A  sample  of  the 
fibre  is  first  boiled  for  five  minutes  in  a  i  per  cent  solution  of 
caustic  soda,  well  washed,  and  then  exposed  for  one  hour  at 
the   ordinary   temperature   to   an  atmosphere   of   chlorin   gas; 
after  which  it  is  removed,  washed,  and  treated  with  an  alkaline 
solution  of  sodium  sulphite,  gradually  raising  to  the  boil.     After 
several  minutes  the  fibre  is  washed,  and  finally  treated  with 
dilute  acetic  acid,  washed,  dried,  and  weighed.     The  residue 
is  taken  as  cellulose,  and  affords  an  important  criterion  as  to 
the  composition  and  value  of  the  raw  fibre. 

(5)  Mercerizing. — This  is  represented  by  the  loss  in  weight 
sustained  by  the  fibre  after  treatment  for  one  hour  cold  with  a 
33  per  cent  solution  of  caustic  potash.     The  action  of  the  alkali 
often  causes  a  considerable  change  in  the  structure  of  the  fibre, 
especially  with  those  fibres  made  up  of  a  number  of  fibrils 
aggregated  into  bundles. 

(6)  Nitration. — This  is  represented  by  the  increase  in  weight 
sustained  by  the  fibre  when  treated  for  one  hour  with  a  mixture 
of  equal  volumes  of  nitric  and  sulphuric  acids.     Any  change 
in  color  is  also  noted. 

(7)  Acid  Purification. — This  is  represented  by  the  loss  in 
weight  sustained  by  the  fibre  after  boiling  with  20  per  cent 
acetic  acid,  washing  with  alcohol  and  water,  and  drying.     This 
treatment  is  intended  to  remove  from  the  fibre  all  accidental 
impurities  with  a  minimum  alteration  in  composition. 

(8)  Carbon  Percentage. — The  fibre  treated  as  above   (7)  is 
subjected  to  a  combustion  in  the  presence  of  chromic  anhydride 
and  sulphuric  acid,  and  the  resulting  gas,  composed  of  a  mixture 
of  carbon  monoxide  and  dioxide,  is  collected  and   measured. 


THE  VEGETABLE   FIBRES 


183 


As  the  two  oxides  of  carbon  have  the  same  molecular  volume, 
the  amount  of  carbon  in  unit  volume  is  independent  of  the 
composition  of  the  gas.  The  amount  of  carbon  in  cotton  cellu- 
lose (the  typical  cellulose)  is  44.4  per  cent;  the  compound 
celluloses,  however,  have  either  a  lower  percentage  in  the  one 
class  (40  to  43  per  cent),  or  a  higher  percentage  in  the  second 
class  (45  to  50  per  cent),  the  pecto-celluloses  being  included  in 
the  first  class  and  the  ligno-celluloses  in  the  second  class.* 

*  The  following  table  shows  the  results  obtained  with  the  principal  fibres 
when  analyzed  by  the  above  method: 


Mois- 
ture, 

% 

Ash, 

% 

Hydrolysis. 

Cellu- 
lose, 

% 

Mercer- 
izing, 

% 

Nitra- 
tion, 

% 

Acid 
Purifi- 
cation, 

% 

Car- 
bon, 

% 

a 

% 

b 

% 

A 

Flax........ 
Ramie      .... 

0-3 
9.0 

7-3 
4-5 

1.6 

2-9 

2-5 

15 

14.6 
13.0 
13.0 

6.2 

22.  2 
24.0 
I7.6 

IO.  I 

81.9 
80.3 

76.5 
88.3 

8.4 
ii  .0 

123.0 
125.0 
153-0 
131.0 

4-5 
6-5 
8-5 
0.8 

43-0 

44-6 
44-3 

Calotropis  .  .  . 
Marsdenia  .  .  . 

4-6 

S.  hemp  

8-5 

i-4 

8-3 

II.7 

83.0 

n-3 

I50-5 

2-7 

47-0 

f  Jute  

10.3 

i  .  i 

13-3 

18.6 

76.0 

ii  .0 

128.0 

2-5 

45-2 

B  < 

Sida  ret  us  a.  .  . 
Urena 

10.7 
10.7 
10.6 

0.6 
1.8 

2.  2 

6.6 
n.  9 

14.0 

12.  2 
I8.S 
19-5 

83-1 
77-7 
73-o 

6.6 
13.6 
16.0 

137.2 

0.4 
4.0 

Hibiscus  can  . 

Hibiscus  sp  .  . 

10.7 

15 

9.8 

14.2 

74.0 

9.6 

3-4> 

45-2 

Agave  amer  .  . 

10.5 

1-4 

IO.O 

20.0 

75-8 

II.  0 

109.8 

i  .  i 

44-9 

C  < 

Sansevieria  sp 
Musa.  .  .    . 

97 
13-4 

12.  2 

12.  O 
II  .O 

16-5 

33-o 
11.  8 

73-i 
64.6 
70.0 

ii  .0 

106.0 

9i-3 
104.0 

2-5 

4-o 

44-5 

Fourcroya.  .  .  . 

CHAPTER  X 
COTTON 

i.  Historical. — The  use  of  cotton  as  a  textile  fibre  dates 
back  to  antiquity,  mention  of  it  being  found  in  the  writings 
of  Herodotus  (445  B.C.)-*  It  was  used  in  India,  Egypt,  and 
China.  The  first  European  country  to  manufacture  cotton 
goods  appears  to  have  been  Spain,  f 

The  use  of  cotton  in  India  dates  back  to  prehistoric  times, 
and  it  is  often  referred  to  as  early  as  800  B.C.  in  the  ancient 
laws  of  Manu.J  It  may  be  stated  that  from  1500  B.C.  to  about 

*  "There  are  trees  which  grow  wild  there  (India),  the  fruit  of  which  is  a  wool 
exceeding  in  beauty  and  goodness  that  of  sheep.  The  Indians  make  their  clothes 
of  this  tree-wool."  (Herodotus,  III,  106.)  The  same  writer  also  refers  to  the 
clothing  of  Xerxes'  army  as  being  composed  of  "cotton  fibre."  (Herodotus,  VII, 
65.)  Theophrastus  (350  B.C.)  gives  a  definite  statement  as  to  manner  in  which 
the  cotton  plant  was  cultivated  in  India  (Hist.  PL,  vol.  4,  p.  132). 

f  A  rather  ambiguous  passage  in  the  Historic,  Critica  de  Espana  indicates 
that  the  manufacture  of  linen,  silk,  and  cotton  existed  in  Spain  as  early  as  the 
ninth  century.  De  Maries  states  that  cotton  manufacture  was  introduced  into 
Spain  during  the  reign  of  Abderahman  III.,  in  the  tenth  century,  by  the  Moors. 
In  the  fourteenth  century  Granada  was  noted  for  its  manufacture  of  cotton. 
A  commercial  historiographer  of  Barcelona  states  that  one  of  the  most  famous 
and  useful  industries  of  that  city  was  the  manufacture  of  cotton;  its  workers 
were  united  in  a  guild  in  the  thirteenth  century,  and  the  names  of  two  of  its 
streets  have  preserved  the  memory  of  the  ancient  locality  of  their  shops.  There 
is  much  uncertainty  as  to  when  the  manufacture  of  cotton  was  first  introduced 
into  England;  the  first  authentic  record  of  such  is  in  Robert's  Treasure  of  Traffic, 
published  in  1641. 

%  The  earliest  mention  of  cotton  appears  to  be  in  the  Asvaldyana  Sranta  Seitra 
(about  800  B.C.).  The  following  quotations  are  from  the  Books  of  Manu.  The 
sacrificial  thread  of  the  Brahmin  must  be  made  of  cotton  (karpasi],  so  as  to  be 
put  over  the  head  in  three  strings  (Book  II,  No.  44).  Let  a  weaver  who  has 
received  10  palas  of  cotton  thread  give  it  back  increased  to  n  by  the  rice-water 
and  the  like  used  in  weaving;  he  who  does  otherwise  shall  pay  a  fine  of  12  panas 
(Book  VIII,  No.  397).  Theft  of  cotton  thread  was  made  punishable  by  fines 

184 


COTTON  185 

the  beginning  of  the  sixteenth  century,  India  was  the  centre 
of  the  cotton  industry,  and  the  cloth  which  was  woven  in 
a  rather  crude  and  primitive  manner  has  rarely  been  equalled 
for  fineness  and  quality.*  Cotton  was  introduced  into  China 
and  Japan  from  India,  but  its  adoption  by  these  countries  was 
slow.f  It  was  probably  introduced  into  China  at  the  time  of 
the  conquest  of  this  country  by  the  Tartars,  but  it  was  not 
until  about  1300  A.D  that  the  fibre  was  cultivated  for  manu- 
facturing purposes.J  In  Egypt  there  is  some  question  as  to 
whether  or  not  cotton  was  used  except  in  rather  late  times, 
flax  being  the  common  article  in  that  country  for  the  manu- 
facture of  cloth.  But  there  is  evidently  a  good  deal  of  con- 

of  three  times  the  value  of  the  article  stolen  (Book  VIII,  No.  236).  In  the  Hebrew 
Scriptures  cotton  is  mentioned  under  the  name  Kirbas  (or  Karpas),  as  when 
describing  the  green  draperies  at  the  palace  of  Susa  (Esther  I,  6).  Among  the 
Latin  authors  of  the  Augustan  age  curtains  and  tents  of  carbasa  are  frequently 
mentioned. 

*  Two  Arabian  travellers  of  the  middle  ages,  writing  of  India,  say:  "In  this 
country  they  make  garments  of  such  extraordinary  perfection  that  nowhere  else 
are  the  like  to  be  seen;  these  garments  are  woven  to  that  degree  of  fineness  that 
they  may  be  drawn  through  a  ring  of  moderate  size."  (Anciennes  Relations 
des  Indes  et  de  la  Chine,  p.  21.)  Marco  Polo  (Book  III,  Ch.  21  and  28),  about 
1298  A.D.,  mentions  India  as  producing  "the  finest  and  most  beautiful  cottons 
that  are  to  be  found  in  any  part  of  the  world."  Ta vernier,  in  his  Travels,  says 
of  India  that  some  calicoes  are  made  so  fine  that  one  can  hardly  feel  them  in  the 
hand,  and  the  thread  when  spun  is  scarcely  discernible;  that  the  rich  have  tur- 
bans of  so  fine  a  cloth  that  30  ells  of  it  weigh  less  than  4  ounces.  The  poetic 
writers  of  the  Orient  call  these  cloths  "webs  of  woven  wind."  There  is  the  record 
of  a  muslin  turban  thirty  yards  in  length,  contained  in  a  cocoanut  set  with  jewels, 
which  was  so  exquisitely  fine  that  it  could  scarcely  be  felt  by  the  touch. 

t  Fesca  (Japanische  Landwirthschaft,  Pt.  II,  p.  485)  says  that  cotton  was 
introduced  into  Japan  accidentally  in  the  year  781  A.D.  from  India,  but  its  cul- 
tivation was  not  continued.  Several  centuries  later  it  was  no  doubt  introduced 
again  by  the  Portuguese;  it  was  not,  however,  until  the  seventeenth  century, 
during  the  reign  of  Tokugawa,  that  the  cultivation  of  cotton  became  at  all  general 
in  Japan.  A  great  deal  of  cotton  is  now  grown  in  Korea,  having  been  introduced 
into  that  country  from  China  about  500  years  ago.  The  Korean  cotton  is  of 
longer  staple  and  of  better  quality  than  the  Chinese  cotton,  as  the  soil  and  climate 
in  Korea  are  better  adapted  to  its  growth.  In  the  seventh  century  the  cotton 
plant  was  used  as  an  ornamental  shrub  in  Chinese  gardens;  and  it  was  not  until 
about  looo  A.D.  that  the  plant  was  commercially  grown  in  China. 

t  Marco  Polo  (Book  II,  Ch.  24)  gives  no  account  of  the  culture  of  cotton  in 
China,  except  in  the  province  of  Fo-Kien,  but  speaks  of  silk  as  being  the  cus- 
tomary dress  of  the  people. 


186  THE  TEXTILE  FIBRES 

fusion  in  the  early  writers  respecting  the  terms  used  for  "  flax  " 
and  "  cotton,"*  and  it  may  be  that  the  ancient  Egyptians  were 
better  acquainted  with  the  use  of  the  cotton  fibre  than  we  imagine; 
we  at  least  know  that  the  cotton  plant  was  grown  there  at  a 
very  early  date.  The  use  of  cotton  was  evidently  known  to 
the  Greeksf  soon  after  the  invasion  of  India  by  Alexander, 
though  this  does  not  signify  that  the  Greeks  themselves  either 
grew  the  cotton  plant  or  engaged  in  the  manufacture  of  the 
fibre  into  clothes.  The  cotton  plant  does  not  appear  to  have 
been  cultivated  in  Italy  until  some  time  after  the  beginning  of  the 
Christian  era,  although  a  knowledge  of  the  fibre  and  a  probable 
use  of  the  cloth  made  from  it  was  no  doubt  known  to  them  a 
long  time  previous.  {  For  the  real  introduction  into  Europe  of 
the  cotton  plant  and  the  manufacture  of  the  fibre  into  cloth  we 
must  look  to  the  Mohammedans,!  who  spread  this  knowledge 

*  Herodotus  states  that  the  Egyptian  priests  wore  linen  clothes,  but  Pliny 
refers  to  them  as  also  wearing  cotton  material,  and  Philostratus  supports  this 
latter  statement.  The  words  translated  as  "linen"  do  not  always  refer  to  the 
fibre  of  which  the  cloth  was  made,  but  often  have  reference  to  the  general  appear- 
ance of  the  material;  therefore,  cloth  made  from  either  flax  or  cotton  alone,  or 
mixed,  was  called  linen.  Even  the  fact  that  all  Egyptian  mummy-cloths  so  far 
examined  appear  to  consist  of  flax  is  no  argument  against  the  probable  use  of 
cotton  by  these  people;  it  only  proves  that  flax  alone  was  employed  for  certain 
religious  purposes,  and  cotton,  wool,  and  silk,  may  have  been  in  common  use 
for  the  clothing  of  the  people. 

t  Aristobulus,  a  contemporary  of  Alexander,  mentions  the  cotton  plant  under 
the  name  of  the  "wool-bearing  tree,"  and  states  that  the  capsules  of  this  tree 
contain  seeds  which  are  taken  out,  and  the  remaining  fibre  is  then  combed  like 
wool.  (Strabo,  XV,  i.)  Nearchus,  an  admiral  of  Alexander,  about  327  B.C., 
says:  "There  are  in  India  trees  bearing,  as  it  were,  bunches  of  wool.  The  natives 
made  linen  garments  of  it,  wearing  a  shirt  which  reached  to  the  middle  of  the 
leg,  a  sheet  folded  about  the  shoulders,  and  a  turban  rolled  around  the  head. 
The  linen  made  by  them  from  this  substance  was  finer  and  whiter  than  any 
other"  (Arrian.  Indika,  Ch.  16),  a  work  compiled  about  150  A.D.  from  the  accounts 
of  various  early  Greek  travellers. 

t  Miiller  (Handbuch  der  klas.  Alterth.  Wissensch.,  vol.  4,  p.  873)  states  that 
cotton  cloth  was  used  for  clothing  by  the  Romans  prior  to  284  A.D. 

§  The  English  word  "cotton"  is,  in  fact,  derived  from  the  Arabic  Katdn  (or 
qutn,  kuteen),  though  it  is  claimed  this  name  originally  denoted  flax.  The  word 
linon  was  itself  at  one  time  used  to  denote  cotton,  and  even  at  the  present  time 
we  speak  of  the  cotton  fibres  as  lint.  In  early  times  it  was  used  rather  to  denote  a 
particular  texture  than  to  describe  a  distinct  fibre.  For  instance,  we  find  "Man- 
chester Cottons"  (1590)  as  a  name  for  a  certain  woolen  fabric. 


COTTON  187 

throughout  the  countries  bordering  on  the  Mediterranean 
Sea  during  the  period  of  their  wide-spread  conquests.*  Eng- 
land first  came  into  prominence  as  a  cotton  manufacturing 
country  in  1635,  the  supply  of  the  raw  fibre  being  obtained 
from  the  East.  Long  previous  to  this,  however,  England  as 
well  as  other  European  countries,  had  imported  cotton  goods 
(calicoes,  etc.)  from  India  by  way  of  Venice.  The  introduction 
of  the  cheaper  cotton  fabrics  was  vigorously  opposed  in  England 
as  being  destructive  of  the  woolen  industry.!  As  to  the  knowl- 
edge and  use  of  cotton  in  the  Western  Hemisphere,  this  also 
seems  to  have  extended  to  very  early  times,  for  when  Columbus 
first  came  to  the  West  Indies  in  1492,  he  found  cotton  exten- 
sively cultivated,  and  the  inhabitants  of  these  islands  wove 
cloth  from  the  fibre.  Among  the  Mexicans  cotton  was  found 
to  be  the  chief  article  of  clothing,  as  these  people  did  not  possess 
either  wool  or  silk  and  were  not  acquainted  with  the  use  of 
flax,  although  the  plant  grew  in  their  country.J  In  Peru 
cotton  was  also  in  use  from  an  early  date,  and  at  the  time  of 
Pizarro's  conquest  of  that  country  in  1522  the  inhabitants 
were  clothed  in  cotton  garments;  cotton  cloths  have  also  been 
found  on  Peruvian  mummies  of  a  very  ancient  date.  Further- 
more, the  cotton  plant  is  indigenous  to  Peru  and  from  it  is 
obtained  a  special  variety  known  as  Peruvian  cotton.  Accord- 
ing to  Bancroft,  the  first  attempt  towards  cotton  cultivation 
in  the  American  colonies  was  in  Virginia,  during  Wyatt's 
administration,  in  162 1.§  The  first  mill  in  the  United  States 

*  Abu  Zacaria  Ebn  el  Awam,  a  Moorish  writer  of  the  twelfth  century,  gives 
a  full  account  of  the  proper  method  of  cultivating  the  cotton  plant,  and  also 
mentions  that  cotton  was  cultivated  in  Sicily. 

f  By  an  Act  of  1720  the  use  and  wear  in  England  of  printed,  painted,  or  dyed 
calicoes  was  prohibited. 

t  Among  the  presents  sent  by  Cortez  to  Charles  V.  of  Spain  were  many  fabrics 
made  from  cotton. 

§  In  1 733  the  cultivation  of  cotton  was  started  in  Carolina,  and  the  following 
year  in  Georgia.  In  1748  the  first  consignment  of  Georgian  cotton  was  sent  to 
England.  In  1758  white  Siam  cotton  was  introduced  into  Louisiana.  In  1784 
fourteen  bales  of  cotton  arrived  in  Liverpool  from  America,  of  which  eight  bales 
we  e  seized  on  the  ground  that  so  much  cotton  could  not  have  been  produced 
in  the  United  States.  In  1786  the  black-seeded  cotton  from  the  Bahamas  was 
introduced  into  Georgia. 


188 


THE  TEXTILE   FIBRES 


for  the  manufacture  of  cotton  goods  appears  to  have  been 
erected  at  Beverly,  Massachusetts,  in  1787.  The  world's 
annual  consumption  of  cotton  at  the  present  time  is  about 
6,500,000,000  Ibs.* 

2.  Origin  and  Growth. — The   cotton   fibre   consists   of   the 
seed-hairs  of  several  species  of  the  genus  Gossypium^  belong- 

*  The  International  Cotton  Federation  (for  1905)  gives  the  following  statistics 
relative  to  the  consumption  of  cotton  by  various  countries: 


Country. 

Spindles. 

Annual 
Total  Bales. 

Consumption, 
Pounds  per 
Spindle. 

Great  Britain      

46,000,000 

3,6oo,OOO 

39-  J 

Germany                   .  .        

8,800,000 

1,625,000 

92  .  3 

France 

6,2OO,OOO 

OOO.OOO 

70   8 

Italy              

2,760,000 

770,000 

139  .  5 

Spain                             

I,7OO,OOO 

3?  I,  OOO 

IO^    2 

Switzerland 

I,4?6  ^46 

103,600 

2(T      C 

Belgium          

972,OOO 

"159,300 

81.9 

Portugal                                    

3  34.IQO 

72,229 

108  o 

Total  Europe   

68,222,736 

7,671,129 

56.2 

United  States  (north)  

15,350,000 

2,112,000 

68.8 

United  States  (south)      

8,5OO,OOO 

2,063,000 

121  .  3 

Total  United  States  

23,850,000 

4,175,000 

87.5 

India 

<?  118  ooo 

2,030  ooo 

108 

Tapan 

1,027,817 

701,987 

341 

Total  Asia 

6  14?  817 

2,731,087 

222 

Grand  total                            .    . 

o8,2i8,??3 

14,578,116 

74 

The  world's  production  of  cotton  for  the  year  1904-5  is  estimated  at  17,782,440 
bales,  of  which  the  United  States  grew  13,420,440  bales,  the  East  Indies  2,960,000, 
Egypt  1,187,000,  Brazil,  etc.,  215,000. 

fThe  following  is  a  description  of  the  botany  of  cotton  given  in  Bulletin 
No.  33  of  the  U.  S.  Department  of  Agriculture:  The  cotton  plant  belongs  to  the 
Malvacea,  or  the  mallow  family,  and  is  known  scientifically  by  the  generic  name 
Gossypium.  It  is  indigenous  principally  to  the  islands  and  maritime  regions  of  the 
tropics,  but  under  cultivation  its  range  has  been  extended  to  40°  or  more  on  either 
side  of  the  equator,  or  to  the  isothermal  line  of  60°  F.  In  the  United  States 


COTTON  189 

ing  to  the  natural  order  of  Malvacece.*  The  cotton  plant 
is  a  shrub  which  reaches  the  height  of  four  to  six  feet.  It 
is  probably  indigenous  to  nearly  all  subtropical  countries, 
though  it  appears  to  be  best  capable  of  cultivation  f  in 
warm,  humid  climates  where  the  soil  is  sandy,  and  in  the 

latitude  37°  north  about  represents  the  limit  of  economic  growth.  The  Gossypium 
plant  is  herbaceous,  shrubby,  or  arborescent,  perennial,  but  in  cultivation  her- 
baceous and  annual  or  biennial,  often  hairy,  with  long,  simple,  or  slightly  branched 
hairs,  or  soft  and  tomentose,  or  hirsute,  or  all  the  pubescence  short  and  stellate, 
rarely  smooth  throughout;  stem,  branches,  petioles,  peduncles,  leaves,  involucre, 
corolla,  ovary,  style,  capsule,  and  sometimes  the  cotyledons  more  or  less  covered 
with  small  black  spots  or  glands.  Roots  tap-rooted,  branching,  long,  and  pene- 
trating the  soil  deeply.  Stems  erect,  terete,  with  dark-colored  ash-red,  or  red 
bark  and  white  wood,  branching  or  spreading  widely.  Branches  terete  or  some- 
what angled,  erect  or  spreading,  or  in  cultivation  sometimes  very  short.  Leaves 
alternate,  petioled,  cordate,  or  subcordate,  3-  to  7-,  or  rarely  q-lobed,  occasionally 
some  of  the  lower  and  upper  ones  entire,  3-  to  7-veined.  Veins  branching  and 
netted;  the  midvein  and  sometimes  adjacent  ones  bear  a  gland  one-third  or 
less  the  distance  from  their  bases,  or  glands  may  be  wholly  absent.  Stipules 
in  pairs,  linear-lanceolate,  acuminate,  often  ceduous.  Flowers  pedunculate. 
Peduncles  subangular  or  angular,  often  thickened  towards  the  ends,  short  or 
very  short,  erect  or  spreading;  the  fruit  is  sometimes  pendulous,  sometimes 
glandular,  bearing  a  leafy  involucre.  Involucre  3-leaved,  or  in  cultivation  some- 
times 4;  bracteoles  often  large,  cordate,  erect,  appressed  or  spreading  at  sum- 
mit, sometimes  coalescent  at  base  or  adnate  to  the  calyx,  dentate  or  laciniate, 
sometimes  entire  or  nearly  so,  rarely  linear.  Calyx  short,  cup-shaped,  truncate, 
shortly  5  dentate  or  more  or  less  5-parted.  Corolla  hypogynous.  Petals  5,  often 
coalescent  at  base  and  by  their  claws  adnate  to  the  lower  part  of  stamen  tube, 
obovate,  more  or  less  unequally  transversely  dilated  at  summit,  convolute  in 
bud.  Staminal  column  dilated  at  base,  arched,  surrounding  the  ovary,  naked 
below,  above  narrowed  and  bearing  the  anthers.  Filaments  numerous,  filiform, 
simple  or  branched,  conspicuous,  exserted.  Anthers  kidney-shaped,  i-celled, 
dehiscent  by  a  semicircular  opening  into  two  halves.  Ovary  sessile,  simple,  3-  to 
5-celled.  Ovules  few  or  many,  in  two  series.  Style  clavate,  3-  to  ^-parted;  divi- 
sions sometimes  erect,  sometimes  twisted  and  adhering  together,  channelled, 
bearing  the  stigmas.  Capsule  more  or  less  thickened,  leathery,  oval,  ovate- 
acuminate,  subglobose,  mucronate,  loculicidally  dehiscent  by  3  to  5  valves.  Seed 
numerous,  subglobose,  ovate  or  subovate,  oblong  or  angular,  densely  covered 
with  cotton  or  rarely  glabrous.  Fibre  sometimes  of  two  kinds,  one  short  and 
closely  adherent  to  the  seed,  the  other  longer,  more  or  less  silky,  of  single  simple 
flattened  cells  more  or  less  spirally  twisted,  more  readily  separable  from  the  seed. 
Albumin  thin,  membranous,  or  none.  Cotyledons  plicate,  auriculate  at  base 
.  enveloping  the  straight  radicle." 

*  The  MalvacecB  is  represented  by  about  one  thousand  different  species,  a  great 
many  of  which  are  of  some  economic  value  to  man. 

t  In  addition  to  the  numerous  varieties  of  cultivated  cottons,  there  are  various 


190 


THE  TEXTILE   FIBRES 


neighborhood  of  the  sea,  lakes,  or  large  rivers.  It  appears 
to  thrive  most  readily  in  North  and  South  America,  India, 
and  Egypt;  it  has  also  been  cultivated  in  Australia,  but 
not  as  yet  with  any  great  degree  of  success;  inferior  qual- 
ities have  been  grown  along  the  coasts  of  Africa;  that  grown 


FIG.  49. — American  Upland  Cotton  Shrub.     (After  Dodge.) 

in  Europe  (Italy  and  Spain)  is  practically  negligible  as  far  as 
commercial  considerations  are  concerned. 

wild  cotton  plants  to  be  met  with  in  many  parts  of  the  world.  With  respect  to 
the  detailed  botany  of  these  wild  plants,  the  reader  is  referred  to  the  very  able 
treatise  by  Sir  George  Watt  on  The  Wild  and  Cultivated  Cotton  Plants  of  the 
World.  As  to  the  general  characteristics  of  these  wild  cottons,  it  may  be  said 
that  they  all  have  a  red-colored  wooly  coating  on  the  testa  of  the  seed.  In  some 
this  assumes  the  condition  of  a  short  dense  velvet,  called  the  fuzz.  In  others, 
there  are  two  coats  of  fibre,  an  under-fleece  (the  fuzz)  and  an  outer  coat  or  floss. 
In  the  third  class  there  is  no  fuzz,  but  a  distinct  floss. 


COTTON 


191 


Monie*  gives  the  following  account  of  the  cultivation  of 
the  cotton  plant:  "  The  plant,  although  indigenous  to  almost 
all  warm  climates,  is  nevertheless  only  cultivated  within  a 
very  limited  area  for  commercial  purposes,  the  principal  cen- 


FIG.  50.— Sea-island  Cotton  Shrub.     (After  Dodge.) 

tres  of  cotton  agriculture  being  in  Egypt,  the  southern  portions 
of  the  United  States,  India,  Brazil,  the  west  and  southern 
coasts  of  Africa,  and  the  West  India  Islands.  A  large  amount 
of  white  cotton  is  raised  in  China,  but  this  is  almost  entirely 

*  The  Cotton  Fibre. 


192 


THE  TEXTILE  FIBRES 


used  in  the  home  manufactures.  The  time  when  sowing  is 
begun  in  the  different  districts  varies  considerably,  being  largely 
dependent  on  climatic  influences.  The  seasons,  however, 
are  generally  as  follows:  American. — From  the  middle  of  March 
to  the  middle  of  April.  Egyptian. — From  the  beginning  of 
March  to  the  end  of  April.  Peruvian  and  Brazilian. — From 
the  end  of  December  to  the  end  of  April.  Indian  or  Surat. — 


FIG.  51. — Leaf  of  the  Cotton  Plant. 

From  May  to  the  beginning  of  August.  In  the  various  American 
plantations  the  sowing  time  begins  and  ends  almost  simul- 
taneously, while  in  other  countries,  especially  where  the  atmos- 
phere and  climate  are  subject  to  much  variation,  the  period 
of  planting  fluctuates;  the  plants  in  some  parts  being  several 
inches  above  the  ground,  while  in  other  parts  of  the  same 
country  the  fields  may  be  only  under  preparation.  When 
the  sowing  is  finished,  and  before,  and  some  time  after  the  crop 


COTTON  193 

makes  its  appearance,  keeping  the  ground  free  from  weeds 
is  the  main  object  to  be  looked  to,  otherwise  the  soil  would  become 
much  impoverished  and  the  product  would  be  of  an  inferior 
quality.  In  from  eight  days  to  a  fortnight  after  sowing,  the 
young  shoots  first  appear  above  ground  in  the  form  of  a  hook, 
but  in  a  few  hours  afterwards  the  seed  end  of  the  stalk  or  stem  is 


FIG.  52.— Leaf  and  Flower  of  Sea-island  Cotton.     (After  Bulletin  No.  33,  U.  S. 

Dept.  Agric.) 

raised  out  of  the  ground,  disclosing  two  leaves  folded  over  and 
closed  together.  The  leaves  and  stems  of  these  young  plants  are 
very  smooth  and  oily  and  of  a  fleshy  color  and  appearance, 
and,  as  before  stated,  extremely  tender  (see  Fig.  54,  a).  In  a  short 
time  after  the  plant  has  reached  the  stage  shown  in  the  illustra- 
tion, it  begins  to  straighten  itself  and  deepen  in  color,  or,  rather, 
changes  to  a  light  olive  green,  while  the  two  leaves  gradually 


194  THE  TEXTILE   FIBRES 

separate  themselves  until  they  attain  the  forms  shown  in  Fig. 
54,  b  and  c.  When  this  stage  has  been  reached  its  develop- 
ment is  rapid,  and  proceeds  in  a  similar  form  to  ordinary  shrubs 
until  it  reaches  maturity.  In  examining  the  cotton  plant 
from  time  to  time  during  its  growth  some  interesting  and 
instructive  objects  will  be  observed.  Firstly,  in  regard  to  the 
formation  of  the  leaves,  it  will  be  found  that  they  vary  in  shape 


FIG.    53. — Leaf   and   Flower  of   India   Cotton,   Gossypium    herbaceum.      (After 
Bulletin  No.  33,  U.  S.  Dept.  Agric.) 

on  different  parts  of  the  stem.  Thus,  for  instance,  on  a  Gallini 
Egyptian  (G.  barbadense)  plant  the  lower  leaves  were  entire, 
the  centre  or  middle  three-lobed,  while  the  upper  leaves  were 
five-lobed.  In  the  G.  hirsutum  species  the  lower  leaves  have 
five,  and  some  three  lobes,  with  the  small  branch  petioles  of 
a  hairy  nature,  while  the  upper  leaves  are  entire  and  undivided. 
In  the  Peruvian  cotton  plant  the  lower  leaves  are  entire  and 
of  an  oval  shape,  while  the  upper  leaves  have  five  acuminated 


COTTON 


195 


lobes.  Another  interesting  point  observable  in  the  growth 
of  the  cotton  plant  is  the  presence  of  a  small  cavity  situated 
at  the  lower  end  of  the  main  vein  under  each  leaf.  Through 
this  opening,  on  warm  days,  the  plant  discharges  any  excess 
of  the  resinous  matter  which  circulates  through  its  branches. 
Before  the  plant  attains  its  full  height  it  begins  to  throw  off 
flower-stalks,  .which  are  generally  (when  perfectly  formed) 
small  in  diameter  and  of  considerable  length;  on  the  extremity 
of  these  stalks  the  blossom  pod  after  a  time  appears,  encased 
in  three  leaf-sheaths  or  calyxes,  with  fringes  of  various  lengths. 
Gradually  this  pod  expands  until  it  attains  to  about  the  size 


a  be 

FIG.  54. — The  Cotton  Plant  in  the  Early  Stages  of  Its  Growth. 

of  a  bean,  when  it  bursts  and  displays  the  blossom.  This 
blossom  only  exists  in  full  development  for  about  twenty- 
four  hours,  when  it  begins  to  revolve  imperceptibly  on  its  axis 
and  in  about  a  day's  time  twists  itself  completely  off.  When 
the  .blossom  has  fallen,  a  small  three-,  and  in  some  cases,  five- 
celled  triangular  capsular  pod  of  a  dark-green  color  is  disclosed, 
which  increases  in  size  until  it  reaches  that  of  a  large  filbert. 
Meantime  the  seeds  and  filaments  have  been  in  course  of 
formation  inside  the  pod,  and  when  growth  is  completed  the 
expansion  of  the  fibre  causes  it  to  burst  into  sections,  in  each  cell 
of  which,  and  adhering  firmly  to  the  surface  of  the  seeds,  is  a 
tuft  of  the  downy  material." 


196 


THE  TEXTILE   FIBRES 


In  America,  India,  and  Egypt  the  cotton  plant  is  .annual 
in  its  growth,  but  in  hot  tropical  climates,  and  in  South  America, 
it  becomes  a  perennial  plant  and  assumes  more  of  a  tree-like 
form,*  The  leaf  of  the  cotton  plant  has  three-pointed  lobes; 


FIG.  55. — Sections  of  the  Cotton  Boll   (Egyptian).      (After  Witt.) 
B,  calyx;  C,  capsule;  D,  seed;  E,  cotton  fibre. 


A,  stem; 


*  According  to  von  Humboldt,  that  portion  of  the  world  lying  between  the 
equator  and  the  34th  degree  of  latitude  presents  the  most  suitable  conditions  for  the 
cultivation  of  the  Gossypium  barbadense,  G.  hirsutum,  and  G.  arborcum  cottons, 
a  mean  yearly  temperature  of  68°  to  86°  F.  being  required.  G.  herbaceum  is  best 
cultivated  in  zones  where  the  temperature  in  winter  does  not  fall  below  50°  F., 
nor  in  summer  rise  above  77°  F.  In  the  United  States  the  cotton  plant  is  culti- 
vated up  to  37°  north  latitude,  but  the  best  fibre  is  obtained  from  along  the  eastern 
coast  between  25°  10',  and  32°  40'  north  latitude,  which  includes  the  states 
of  Florida,  Georgia,  and  South  Carolina.  Proximity  to  the  sea  appears  to  have  a 
beneficial  influence  on  the  quality  of  the  cotton  fibre,  due  no  doubt  to  the  salt- 
laden  air  and  soil.  This  same  fact  is  to  be  observed  in  Indian  and  Egyptian 
cottons.  In  fact,  the  only  exception  to  this  rule  appears  to  be  Brazilian  cotton, 
that  from  the  inland  districts  being  of  superior  quality  to  that  produced  along 


COTTON  197 

the  flower  has  five  petals,  yellow  at  the  base,  but  becoming 
almost  white  at  the  edges.  The  fruit  of  the  cotton  plant  forms 
the  cotton  boll,  which  contains  the  seeds  with  the  attached 
fibres.*  The  boll  consists  of  from  three  to  five  segments,  and 
on  ripening  bursts  open  and  discloses  a  mass  of  pearly  white 
downy  fibres  (Fig.  55),  in  which  are  imbedded  the  brownish 
black  to  black-colored  cottonseeds.  The  time  required  for  the 
maturity  of  cotton  is  divided  as  follows:  From  seeding  to  flower- 
ing. New  Orleans  80  to  90  days,  sea-island  100  to  no  days; 
from  flowering  to  maturity,  New  Orleans  70  to  80  days,  and 
sea-island  about  80  days,  making  the  total  period  of  growth 
about  5  to  6J  months.  |  The  cotton  should  be  picked  as  soon 
as  possible  after  ripening;  the  seeds  are  then  separated  from, 
the  fibres  by  a  process  known  as  ginning.^.  Besides  the  fibre 

the  coast.  The  reason  for  this,  however,  is  that  the  coast  districts  of  Brazil  have 
an  excessive  rainfall  during  nearly  nine  months  of  the  year.  In  China  and  Japan 
cotton  is  cultivated  readily  as  far  north  as  41°,  and  in  Europe  (Black  Sea 
provinces)  its  cultivation  reaches  to  46°. 

*  The  cotton  fibre  is  developed  as  a  protective  covering  to  the  young  seeds 
while  still  in  their  embryonic  condition.  This  provision  is  not  restricted  to  the 
cotton  plant  alone,  but  is  common  to  many  other  species. 

f  Heuze,  Plantes  Industrielles,  vol.  i,  p.  139. 

J  Cotton  which  has  been  picked  from  the  plant  and  still  contains  the  seed, 
is  known  as  "seed  cotton."  Before  the  ginning  process  proper  the  seed  cotton 
is  often  passed  through  cleaners  for  the  purpose  of  breaking  up  any  unopened 
bolls  and  disintegrating  lumps  of  dirt,  burrs,  etc.,  which  may  be  mingled  with 
the  cotton  fibres.  The  principle  on  which  the  ginning  depends  is  to  pull  the 
fibre  through  a  narrow  space  which  is  too  small  to  permit  of  the  seed  following. 
There  are  two  types  of  cotton  gins,  the  roller  gin  and  the  saw  gin.  The  former 
is  only  used  for  long  stapled  cottons  where  the  chief  consideration  is  to  preserve 
the  length  of  the  fibre.  It  has  a  much  lower  production  in  a  given  time  than  the 
saw  gin.  The  latter  was  the  invention  of  Eli  Whitney,  and  is  still  the  same  in 
principle  as  when  first  invented  in  1793.  Briefly  described,  the  saw  gin  consists 
of  a  box  or  hopper  for  holding  the  seed  cotton;  one  side  of  this  box  is  a  grate 
composed  of  steel  bars,  through  the  intervals  of  which  a  number  of  thin  steel 
discs,  notched  on  the  edge  (saws),  rotate  rapidly.  The  fibres  are  caught  in  the 
notches  or  teeth  of  these  discs  and  thus  pulled  from  the  seeds,  the  latter  as  they 
are  cleaned  fall  down  through  a  slit  below  the  grate.  The  fibres  are  carried  off 
the  revolving  saws  by  means  of  a  rapidly  rotating  cylindrical  brush.  The  cotton 
fibre  as  ginned  from  the  seed  is  technically  known  as  "lint."  In  upland  or 
ordinary  American  cotton,  the  seeds  are  not  entirely  freed  from  fibre  by  the 
ginning,  there  remaining  more  or  less  short  fibre  together  with  a  fine  undergrowth 
of  fibre,  amounting  on  an  average  to  about  10  per  cent  of  the  total  weight  of  the 


198 


THE  TEXTILE  FIBRES 


itself,  nearly  all  of  the  other  products  of  the  cotton  are  now 
utilized  commercially.*  The  seeds  are  of  especial  value,  as 
they  contain  a  large  quantity  of  oil,  which  is  expressed  and 
used  for  soapmaking  and  many  other  purposes,!  while  the 

seed.  At  the  present  time  these  seeds  are  further  delinted  by  passing  through 
specially  constructed  gins  having  saw-teeth  closer  set  and  finer.  The  fibre  obtained 
in  this  manner  is  known  as  "linters,"  and  is  chiefly  used  for  cotton-batting  or 
is  converted  into  guncotton. 

*  According  to  Bulletin  No.  33  (U.  S.  Dept.  Agric.)  the  following  is  the  pro- 
portion of  the  different  parts  of  the  cotton  plant,  calculated  on  the  dried  or  water- 
free  material: 


Part  of  the  Plant. 

Weight. 

Per  Cenl. 

Ounces. 

Grams. 

Roots 

0-5I3 
1-350 
1.181 
0.829 

1-343 
0.615 

14-55 
38-26 
33.48 
23-49 
38-07 

17-45 

8.80 

23-IS 
20.25 
14.  21 
23.03 
10.56 

Stems  

Leaves  ...          .  .        ... 

Bolls 

Seed  

Lint  (fibre)  ... 

Total  

5-831 

165.30 

IOO.OO 

This  table  was  compiled  from  the  examination  of  a  large  number  of  plants 
and  represents  the  average  composition  of  the  cotton iplant  as  stated. 

f  The  following  table  shows  the  products  obtainable  from  2000  Ibs.  of  cotton- 
seed: 

A.  Linters,    27  Ibs. 

B.  Hulls,     841  Ibs. 

1.  Bran,  Feeding  stuffs. 

2.  Fibre,  High-grade  paper. 

3.  Fuel,  Ashes  and  fertilizer. 

C.  Meats,  1012  Ibs. 

1.  Cake,  732  Ibs. 

(a)  Meal. 

(1)  Feeding  stuff. 

(2)  Fertilizer. 

2.  Crude  oil.  280  Ibs. 

(a)  Soap  stock,  soaps. 

(b)  Summer  yellow. 

(1)  Winter  yellow. 

(2)  Salad  oil. 

(3)  Cotton  lard. 

(4)  Cottolene. 

(5)  Miner's  oil. 

(6)  Soap. 


COTTON 


199 


residuum  of  meal  and  hulls  is  converted  into  cattle  foods  and 
fertilizer.*  The  short  fibres,  or  nep,  left  on  the  seed  after  the 
first  ginning  are  also  recovered  by  a  second  process  and  are 
known  as  linters,  which  are  used  in  the  manufacture  of  cotton- 
batting,  guncotton,  etc.  With  sea-island  and  Egyptian  cottons 
the  seed  is  entirely  freed  from  lint  by  ginning,  but  with  upland 
cottons  the  quantity  of  lint  still  adhering  to  the  seed  after  it 
has  passed  through  the  gin  amounts  to  about  10  per  cent  of 
the  total  weight  of  the  seed.j  The  separation  of  seed- 

*  The  following  table  presents  the  fertilizing  constituents  in  a  crop  of  cotton 
yielding  100  Ibs.  of  lint  per  acre,  expressed  in  pounds  per  acre.  The  weight  of 
the  total  crop  from  the  acre  was  847  Ibs. 


Part  of  Plant. 

Nitrogen. 

Phos- 
phoric 
Acid. 

Potashl 

Lime. 

Magnesia. 

Roots  (83  Ibs.)        .    ...    ... 

o   76 

O  43 

I   06 

O    <?3 

O    34 

Stems  (219  Ibs  ) 

3    2O 

I    20 

3    OQ 

2    12 

o  02 

Leaves  (192  Ibs.)  
Bolls  (135  Ibs.)                    .  .'.  .  ;  . 

6.16 
3   43 

2.28 
I    3O 

3-46 
2    44 

8.52 
o  60 

1.67 

O    ^4 

Seed  (218  Ibs  ) 

6  82 

2    77 

2  s<; 

O    <5J 

I    2O 

Lint  

o.  34 

O.  IO 

0.46 

O    IO 

o  08 

j 

Total  (847  Ibs.)  

20.  71 

8.17 

13.06 

I  2.  60 

4-75 

The  following  table  presents  the  proximate  constituents  of  the  various  parts 
of  the  cotton  plant  as  given  by  analyses  of  a  large  number  of  samples  by  the 
United  States  Department  of  Agriculture: 


Part  of  Plant. 

Water. 

Ash. 

Protein. 

Fibre. 

Nitrogen- 
free 
Extract. 

Fat. 

Entire  plant  

IO.OO 

12  .OI 

17    C7 

22    04 

3  ^    II 

4j  r 

Roots  

IO.OO 

7.  23 

o  80 

48    ^7 

3O    1  1 

2    77 

Stems  

IO    OO 

964 

2O   4^ 

4O    44 

3O    87 

Leaves  

IO    OO 

12    87 

21    64 

12    ^7 

36    82 

•  Ou 

Bolls 

IO   OO 

4OO 

i  <;  80 

IO    72 

Seed 

9    02 

474 

10  38 

22     C7 

•°7 

Lint 

61  A. 

i  6<J 

82     7T 

Z6  •  V4 

J9-45 

i  .v$ 

1  •  ou 

°6  •  i  *• 

•  /y 

fAn  Experiment  Station  Report  shows  that  the  seeds  from  upland  cotton 
after  ginning  consist  of  54.22  per  cent  of  kernels  (yielding  36.88  per  cent  of  oil 
and  63.12  per  cent  of  meal)  and  45.78  per  cent  of  hulls  (yielding  27.95  per  cent 


200 


THE  TEXTILE   FIBRES 


particles  from  the  fibre  is  not  always  perfect,  and  frequently  these 
particles  make  their  appearance  in  gray  calico  in  the  form  of  black 
specks  or  motes,  and  as  they  contain  small  quantities  of  oil 
and  tannin  matters  which  are  pressed  out  into  the  surrounding 
fibres,  they  cause  specks  and  unevenness  in  dyeing  and  finish- 
ing. If  they  come  in  contact  with  solutions  or  materials 
containing  iron  compounds,  a  violet  stain  will  be  produced, 
the  color  of  which,  however,  may  not  develop  for  some  months. 


FIG.  56. — Typical  Cotton  Fibres.  (Xaoo).  A,  normal  fibre  showing  regular 
twists;  B,  straight  fibre  without  twists;  C,  a  knot  or  irregularity  in  growth 
of  fibre.  (Micrograph  by  author.) 

Bowman  gives  an  excellent  description  of  the  physiologi- 
cal development  of  the  cotton  fibre,*  from  which  the  following 

of  linters  and  72.05  per  cent  residue);  so  that  in  the  ginned  seed  there  is  present 
the  following: 


Meal .  . 
Oil.... 
Hulls .  . 
Linters 


Per  Cent. 
34.22 
2O.OO 
35.78 

,     IO.OO 


According  to  Adriane  (Chem.  News,  Jan.,  1865)  the  seeds  from  Egyptian  cotton 
yield  37.45  per  cent  of  hulls  and  62.55  per  cent  of  kernels. 

*The  following  remarks  relative  to -the  development  of  the  cotton  fibre  from 
the  seed  are  taken  from  Bulletin  No.  33  (vide  supra):  "If  a  very  immature  cotton 
boll  be  cut  transversely,  the  cut  section  will  show  that  it  is  divided  by  longi- 
tudinal walls  into  three  or  more  divisions,  and  the  seeds  will  be  shown  attached 


COTTON  201 

is  quoted:  "  In  their  earliest  stages  the  young  cotton  fibres 
appear  to  have  a  circular  section  arising  from  the  compara- 
tive thickness  of  the  tube- walls;  but  as  these  walls  gradually 
become  thinner  by  the  longitudinal  growth  of  the  hair  and  the 
pressure  to  which  they  are  subjected  by  the  contact  of  surround- 
ing fibres  enclosed  within  the  pod,  they  gradually  become 
flattened,  and  just  before  the  pod  bursts  the  outer  walls  of  the 
cells  have  become  so  attenuated  in  the  longest  fibres  as  to  be 


FIG.  57. — Typical  Cotton  Fibres.  (Xsoo.)  A,  broad  flat  fibre  near  base;  B, 
thick  rounded  fibre;  C,  fibre  near  pointed  end;  D,  cut  end  of  fibre.  (Micro- 
graph by  author.) 

almost  invisible  even  under  high  microscopic  powers,  and  present 
the  appearance  of  a  thin,  pellucid,  transparent  ribbon.  With 

to  the  inner  angle  of  each  division.  The  seeds  retain  this  attachment  until  they 
have  nearly  reached  their  mature  size  and  the  growth  of  lint  has  begun  on  them, 
when  their  attachments  begin  to  be  absorbed,  and  by  the  increased  growth  of 
the  lint  the  seeds  are  forced  into  the  centre  of  th'e  cavity.  The  development  of 
the  fibre  commences  at  the  end  of  the  seed  farthest  from  its  attachment  and 
gradually  spreads  over  the  seed  as  the  process  of  growth  continues.  The  first 
appearance  of  the  cotton  fibre  occurs  a  considerable  time  before  the  seed  has 
attained  its  full  growth  and  commences  by  the  development  of  cells  from  the 
surface  of  the  seed.  These  cells  seem  to  have  their  origin  in  the  second  layer 
of  cellular  tissue,  and  force  themselves  through  the  epidermal  layer,  which  seems 
to  be  gradually  absorbed.  The  cells  which  originate  the  fibre  are  characterized 
by  the  thickness  of  their  cell-walls  when  compared  with  their  diameter." 


202  THE  TEXTILE  FIBRES 

the  bursting  of  the  pod,  however,  a  change  occurs.  The  admis- 
sion of  air  and  sunlight  causes  a  gradual  unfolding  of  the  hairy 
plexus,  and  the  rapid  consolidation  of  the  liquid  cell-contents 
on  the  inner  surface  of  the  cell-wall  gives  them  a  greater  thick- 
ness and  density,  which  is  further  increased  by  the  gradual 
shrinking  in  of  the  walls  themselves  upon  the  cell-contents. 
There  is  also  a  gradual  rounding  and  thickening  of  the  fibre, 
which  increases  by  the  deposition  of  matter  on  the  inner  wall 
of  the  cell.  As  this  action  is  not  perfectly  uniform,  arising 
from  the  unequal  exposure  of  different  parts  of  the  fibres  to 
light  and  air,  it  causes  a  twisting  of  the  hairs,  which  is  always 
a  characteristic  of  cotton  when  viewed  under  the  microscope, 
and  the  flat  collapsed  portions  of  the  tube  form  so  many  reflect- 
ing surfaces,  to  which  the  brightness  of  the  fibre  when  stretched 
tight  in  the  fingers  is  no  doubt  due.  Another  change  also 
occurs  at  this  stage,  a  change  which  corresponds  to  the  ripen- 
ing of  fruit.  In  the  earliest  period  of  their  formation  the 
growing  cells  are  filled  with  juices  which  are  more  or  less  astringent 
in  character,  tinder  the  influence  of  light  and  air  these  cell- 
contents  undergo  a  chemical  change,  in  which  the  astringent 
principles  are  replaced  by  more  or  less  saccharine  or  neutral 
juices,  until  in  the  perfectly  ripe  cotton  fibre  the  cell-walls 
are  composed  of  almost  pure  cellulose." 

Flatters  *  gives  a  detailed  description  of  the  physiology 
of  the  cotton  fibre,  from  which  the  following  is  adapted:  Soon 
after  the  fertilization  of  the  ovum  of  the  flower  certain  structural 
differences  begin  to  appear  in  the  cuticle  cells  forming  the  wall 
of  the  ovary.  A  thin  layer  of  protoplasm  is  soon  formed  around 
the  inner  wall  of  the  cell.  Intervening  cells  begin  to  elongate 
until  the  entire  surface  of  the  ovule  presents  the  appearance 
of  being  covered  with  minute  protuberances.  These  continue 
to  elongate  until  a  definite  fibril  covering  is  attained.  At  the 
commencement  of  this  cuticular  differentiation  the  underlying 
tissue  is  gorged  with  protoplasm,  in  which  food  substances  are 
imbedded,  but  which  soon  become  absorbed  by  the  developing 

*  The  Cotton  Plant,  p.  59.  A  very  complete  description  of  the  physiology  of 
the  entire  cotton  plant  is  also  given  in  this  book,  see  pp.  17,  et  seq. 


COTTON 


203 


fibres.  This  fibril  development  is  coincident  with  the  forma- 
tion and  development  of  the  embryo,  and  serves  as  a  protective 
covering  for  it.  In  addition  to  the  protoplasm  and  nucleus 
there  are  found  in  the  cotton  fibre  during  its  development  and 
its  maturity  minute  microscopic  bodies,  the  endochrome*  The 
presence  or  absence  of  this  endochrome  determines  the  color 
of  the  fibre,  which  in  some  types  becomes  definite  by  imparting 
to  it  a  deep  brown  color,  as  in  "  brown  Egyptian,"  and  a  still 
deeper  color,  as  in  "  red  Peruvian."  Endochrome  is  found 
more  or  less  in  every  class  of  cotton.  It  does  not,  except  in  a 


FIG.  58. — Cotton  Bolls. 

few  cases,  permeate  the  cell-wall  of  the  fibre,  but  becomes 
coagulated  as  the  fibre  matures,  and  forms  a  central  core  in  the 
fibril  cavity.  It  is  this  core  which  imparts  to  the  fibre  its 
color  by  reflection  through  the  transparent  cell- wall. 

*  The  presence  of  the  endochrome  is  more  emphasized  in  wild  cottons  than 
in  the  cultivated  species.  On  this  account  the  fibre  of  nearly  all  wild  cotton 
plants  has  a  deep  rusty  tint  (Khaki  or  red  cotton).  Watt  (Wild  and  Cultivated 
Cotton  Plants,  p.  28)  states  that  so  very  constant  is  this  peculiarity  of  the  uncul- 
tivated cottons,  that  its  appearance  in  the  field  may  be  accepted  as  an  almost 
certain  sign  of  a  low-grade  plant,  or  of  defective  cultivation,  or  unsuitable  environ- 
ment. It  is  in  all  probability  a  sign  of  "reversion"  to  an  ancestral  and  pre- 
sumably hardier  or  more  prepotent  condition. 


204  THE  TEXTILE  FIBRES 

Flatters  concludes  that  the  cotton  fibre  is  made  up  of  three 
primary  elements,  (a)  the  cuticular  envelope;  (b)  the  secondary 
deposit  of  cellulose;  (c)  the  endochromic  coloring  matter. 

The  cell-wall  of  the  cotton  is  thin  in  comparison  with  that 
of  the  bast  fibres,  but  in  comparison  with  the  other  seed-hairs 
it  is.  remarkably  thick.  This  accounts  for  its  much  greater 
strength  over  the  latter.  In  completely  developed  fibres  the 
thickness  of  the  cell-wall  is  from  one-third  to  two-thirds  of  the 
total  thickness  of  the  fibre  itself. 

The  quality  of  the  cotton  fibre  depends  not  only  on  the 
species  of  the  plant  from  which  it  is  derived,  but  also  on  the 
manner  of  its  cultivation.  The  conditions  which  exercise, 
perhaps,  the  greatest  influence  are:  (a)  the  seed,  (b)  the  soil, 
(c)  the  mode  of  cultivation,  (d)  the  climatic  conditions.*  The 
seed  for  sowing  must  be  carefully  and  specially  chosen  for  the 
purpose.  A  very  dry  soil  produces  harsh  and  brittle  cotton, 
the  fibres  of  which  are  very  irregular  in  length;  a  moist  and 
sandy  soil  produces  a  very  desirable  cotton  of  long  and  fine 
staple,  f  The  best  soil  is  considered  to  be  a  light  loam,  while 
a  damp  clay  is  regarded  as  the  worst.  Soils  situated  in  prox- 
imity to  the  sea,  and  therefore  containing  considerable  saline 
matter,  appear  to  furnish  the  most  valuable  varieties  of  cotton, 
and  it  is  claimed  that  the  saline  constituents  of  the  soil  have 
considerable  influence  on  the  growth  and  development  of  the 
cotton  fibre.  J 

*  It  is  said  that  the  best  average  daily  temperature  for  the  growth  of  cotton 
is  from  60°  to  68°  F.  for  the  period  from  germination  to  flowering,  and  from  68° 
to  78°  F.  from  flowering  to  maturity.  According  to  Dr.  Wight  (Jour.  Agr.  Hort. 
Soc.  India,  vol.  7,  p.  23),  for  the  proper  maturing  of  the  best  qualities  of  American 
cotton  an  increasing  temperature  during  the  period  of  greatest  growth  is  required; 
the  failure  to  produce  in  India  a  quality  of  fibre  equal  to  the  American  product 
from  the  same  kind  of  seed  is  attributed  to  the  fact  that  in  the  climate  of  the  former 
country  there  exists  a  diminishing  rather  than  an  increasing  average  daily  tem- 
perature. 

f  An  excess  of  rain  causes  the  plant  itself  to  grow  too  rapidly  and  luxuriantly 
at  the  expense  of  the  fruit  and  consequently  there  is  less  fibre  produced.  A  long 
drought  causes  a  stunted  growth  of  the  plant,  but  few  bolls  are  produced,  and 
these  ripen  prematurely. 

J  Flatters  (The  Cotton  Plant,  p.  10)  states  that  a  humid  temperature  ranging 
from  70°  upwards,  and  a  soil  of  a  deep  loamy  nature  in  which  alkaline  and 


COTTOX  205 

3.  Varieties  of  Cotton.* — The  classification  of  the  different 
species  of  cotton  plant  varies  with  different  authorities  ;  the 
most  comprehensive,  perhaps,  is  to  classify  the  different 
varieties  of  the  cotton  plant  as  (i)  the  tree,  (2)  the  shrub,  and 
(3)  the  herbaceous  species. 

The  following  is  a  list  of  species  of  the  cotton  plant  more 
or  less  recognized  by  botanists: 

Gossypium  album  Hamilton,  a  synonym  of  G.  herbaceum; 

commercially  known  as  upland    cotton;     has    a   white 

seed. 
G.  arboreum  Linn.,  a  tree-like  plant;   perennial;   indigenous 

to  India;    produces  but  little  fibre. 
G.  barbadense   Linn.,    indigenous   to   America  and  outlying 

islands;   gives  the  highly  prized  sea-island  cotton. 
G.  brasiliense  Macfad.,  a  tropical  species;    belongs  to  the 

so-called  "  kidney  cottons;"    the  seeds  adhere  to  one 

another  in  clusters. 
G.  chinense  Fisch  &  Otto,  a  synonym  for  G.  herbaceum;    a 

Chinese  cotton. 

calcareous  salts  are  present,  and  which  contains  at  least  3  per  cent  of  phosphoric 
acid,  seem  to  be  the  most  suitable  conditions  for  the  successful  cultivation  of  the 
cotton  plant. 

*  The  various  names  given  to  the  cotton  fibre  in  different  countries  may  be 
of  interest;   they  are  as  follows: 

India Pucti 

Spain Algodon 

Yucatan  and  ancient  Mexico Ychcaxihitvitl 

Tahiti Vavai 

France Coton 

Italy Cotone 

Germany Baumwolle 

Persia ; Pembeh  or  Poombeh 

Arabia Gatn,  Kotan,  or  Kutn 

Cochin  China Cay  Haung 

China Hoa  mein 

Japan Watta  ik  or  Watta  noki 

Siam Tonfaa 

Hindoostan Nurma 

Mysore  and  Bombay Deo  Kurpas  and  Deo  Kapas 

Mongolia Kohung 


206  THE  TEXTILE   FIBRES 

G.  croceum  Hamilton,  a  synonym  for  G.  herbaceum;  possesses 

a  yellow  lint. 

G.  eglandulosum  Cav.,  a  synonym  for  G.  herbaceum. 
G.  datum  Salisb.,  a  synonym  for  G.  herbaceum. 
G.  fructescens  Lasteyr.,  a  synonym  for  G.  barbadense. 
G.  fuscum  Roxb.,  a  synonym  for  G.  barbadense. 
G.  glabrum  Lam.,  a  synonym  for  G.  barbadense. 
G.  glandulosum  Steud.,  a  synonym  for  G.  herbaceum. 
G.   herbaceum  Linn.,   usually  considered  of  Asiatic  origin; 

synonymous  with  G.  hirsutum;  ordinary  upland  cotton. 
G.  hirsutum   Linn.,    of   American    origin  ;    Georgia    upland 

cotton. 

G.  indicum  Lam.,  a  synonym  for  G.  herbaceum. 
G.  jamaicense  Macfad.,  a  synonym  for  G.  barbadense;   grows 

in  Jamaica. 
G.  javanicum  Blume,  a  synonym  for  G.  barbadense;    grows 

in  Java. 
G.  kirkii  Masters,  a  wild  African  species  never  found  under 

cultivation;  the  only  known  variety  of  which  the  seed 

is  left  quite  naked  by  removal  of  the  fibres. 
G.  latifolium  Murr.,  a  synonym  for  G.  herbaceum. 
G.  leoninum  Medic.,  a  synonym  for  G.  herbaceum. 
G.  macedonicum  Murr.,  a  synonym  for  G.  herbaceum. 
G.  maritimum  Tod.,  a  synonym  for  G.  barbadense. 
G.  micranthum  Cav.,  a  synonym  for  G.  herbaceum. 
G.  molle  Mauri,  a  synonym  for  G.  herbaceum. 
G.  nanking  Meyen,  a  synonym  for  G.  herbaceum. 
G.  neglectum    Tod.,    indigenous    to    India;     similar     to    G. 

aboreum;  extensively  grown  in  India;  gives  the  Dacca 

and  China  cottons. 

G.  nigrum  Hamilton,  a  synonym  for  G.  barbadense. 
G.  obtusifolium  Roxb.,  a  synonym  for  G.  herbaceum,  a  dis- 
tinctly Oriental  species  to  be  met  with  in  India,  Ceylon, 

etc. 

G.  oligospermum  Macfad.,  a  synonym  for  G.  barbadense. 
G.  paniculatum  Blanco,  a  synonym  for  G.  herbaceum. 
G.  perenne  Blanco,  a  synonym  for  G.  barbadense. 


COTTON  207 

• 
G.  peruvianum  Cav.,  a  synonym  for  G.  barbadense. 

G.  punctatum  Schum.  &  Thonn.,  a  synonym  for  G.  barbadense. 

G.  racemosum  Poir,  a  synonym  for  G.  barbadense. 

G.  religiosum  Par.,  a  synonym  for  G.  arboreum;  so  called 
because  its  use  is  mostly  restricted  to  making  turbans 
for  Indian  priests;  also  because  it  grows  in  the  gardens 
of  the  temples;  it  has  the  cultural  name  of  Nurma 
or  Deo  cotton.  Also  a  variety  of  G.  barbadense. 

G.  roxburghianum  Tod.,  a  variety  of  G.  neglectum ;  cor- 
responds to  the  Dacca  cotton  of  India. 

G.  siamense  Tenore,  a  synonym  for  G.  herbaceum. 

G.  sinense  Fisch.,  a  synonym  for  G.  herbaceum. 

G.  stocksii  Masters,  a  synonym  for  G.  herbaceum;  claimed 
to  be  the  original  of  all  cultivated  forms  of  this  latter 
species. 

G.  strictum  Medic.,  a  synonym  for  G.  herbaceum. 

G.  tomentosum  Nutt,  indigenous  to  the  Hawaiian  Islands 
where  it  is  known  as  Mao  or  Huluhulu  cotton;  the 
bark  is  used  for  making  twine. 

G.  tricuspidatum  Lam.,  a  synonym  for  G.  herbaceum. 

G.  mtifolium  Lam.,  a  synonym  for  G.  barbadense.     ;'  • 

G.  mtifolium  Roxb.,  a  synonym  for  G.  herbaceum. 

G.  wightianum  Tod.,  a  synonym  for  G.  herbaceum;  claimed 
by  Todaro  to  be  the  primitive  form  of  the  Indian 
cottons.  It  furnishes  the  so-called  long-stapled  or 
gujarat  cotton  of  India. 

According  to  Parlatore  all  commercial  cotton  is  derived 
from  seven  species  of  the  Gossypium,  which  he  enumerates 
as  follows:* 

(i)  G.  barbadense^  which  comprises   the  long-stapled   and 

*  Filippo  Parlatore,  Le  specie  del  cotoni,  1866. 

t  The  botany  of  this  species  is  given  as  follows:  Shrubby,  perennial,  6  to  8  feet 
high,  but  in  cultivation  herbaceous  and  annual  or  biennial,  3  to  4  feet  high, 
glabrous,  dotted  with  more  or  less  prominent  black  glands.  Stems  erect,  terete 
branching.  Branches  graceful,  spreading,  subpyramidal,  somewhat  angular, 
ascending,  at  length  recurving.  Leaves  alternate,  petiolate,  as  long  as  the  petioles, 
rotund,  ovate,  subcordate,  3-  to  5-lobed,  sometimes  with  some  of  the  upper  and 
lower  leaves  entire,  cordate,  ovate,  acuminate;  lobes  ovate,  ovate-lanceolate, 


"208  THE  TEXTILE  FIBRES 

silky-fibred  cottons  known  as  Barbadoes,  sea-island,  Egyptian, 
and  Peruvian.  The  plant  reaches  a  height  of  from  6  to  8  feet, 
and  has  yellow  blossoms  becoming  purple  toward  the  base. 
The  seeds  are  small  in  size  and  of  a  black  color,  and  are  particu- 
ularly  distinguished  from  those  of  ordinary  American  cotton 
in  that  they  do  not  possess  a  fine  undergrowth  of  short  hairs 
(neps) ;  consequently  when  ginned  the  seed  comes  out  clean  and 
smooth.  Owing  to  variations  in  the  conditions  of  its  cultiva- 
tion, however,  the  present  sea-island  cotton  has  changed  con- 
siderably from  the  original  barbadense*  Georgia  uplands 
or  boweds  cotton  is  presumably  a  variety  of  this  species  modified 
by  cultivation  on  the  mainland.  This  variety  is  employed 
for  the  spinning  of  fine  yarns,  such  as  are  known  in  trade  as 
"  Bolton  counts." 

(2)  G.  herbaceum^  including  most  of  the  cotton  from  India, 

acute  or  acuminate,  channelled  above,  sinus  subrotund,  above  green,  lighter  on 
the  veins,  glabrous,  beneath  pale  green  and  glabrous,  3-  to  5-veined,  the  mid- 
vein  and  sometimes  one  or  both  pairs  of  lateral  veins  bearing  a  dark-green  gland 
near  their  bases.  Stipules  erect  or  spreading,  curved,  lanceolate-acuminate^ 
entire  or  somewhat  laciniate.  Peduncles  equal  to  or  shorter  than  the  petiole, 
erect,  elongating  after  flowering,  rather  thick,  angled,  sometimes  bearing  a  large 
oval  gland  below  the  involucre.  Involucre  3-parted,  erect,  segments  spreading 
at  top,  many  veined,  broadly  cordate-ovate,  exceeding  half  the  length  of  the 
corolla,  9  to  12  divided  at  top,  divisions  lanceolate-acuminate.  Calyx  much 
shorter  than  the  involucre,  bracts  cup-shaped,  slightly  5-toothed  or  entire.  Corolla 
longer  than  the  bracts.  Petals  open,  but  not  widely  expanding  after  flower- 
ing, broadly  obovate,  obtuse,  crenate,  or  undulate  margined,  yellow  or  sulphur 
colored,  with  a  purple  spot  on  the  claw,  all  becoming  purplish  in  age.  Stamen 
about  half  the  length  of  the  corolla,  the  tube  naked  below,  anther  bearing  above. 
Style  equal  to  or  exceeding  the  stamens,  3  to  5  parted.  Ovary  ovate,  acute, 
glandular,  3-,  rarely  4-  to  5-celled.  Capsule  a  little  longer  than  the  persistent 
involucre,  oval,  acuminate,  green,  shining,  3-,  rarely  4-  to  5-valved.  Valves 
oblong  or  ovate-oblong,  acuminate,  the  points  widely  spreading.  Seeds  6  to  9  in 
each  cell,  obovate,  narrowed  at  base,  black.  Fibre  white,  3  to  4  or  more  times 
the  length  of  the  seed,  silky,  easily  separable  from  the  seed.  Cotyledons  yellow- 
ish, glandular,  punctate. 

*  The  following  species  are  considered  as  synonyms  of  G.  barbadense:  G.  fruc- 
tescens  Lasteyr.,  G.  fuscum  Roxb.,  G.  glabrnm  Lam.,  G.  jamaicense  Macfad., 
G.  javanicum  Blume,  G.  maritimum  Todaro,  G.  nigrum  Ham..  G.  oligospermnm 
Macfad.,  G.  perenne  Blanco,  G.  peruvianum  Cav.,  G.  punctatum  Schum.  &  Thonn., 
G.  racemosum  Poir.,  G.  religiosum  Par.,  and  G.  vitifolium  Roxb. 

t  The  descriptive  botany  of  this  specie?  is  as  follows:  Shrubby,  perennial, 
but  in  cultivation  herbaceous,  annual  or  biennial.  Pubescence  variable,  part 


COTTON  209  - 

southern  Asia,  China,  and  Italy.*  It  is  an  annual  plant  grow- 
ing from  5  to  6  feet  in  height;  unlike  the  barbadense  variety,  its 
seeds  are  generally  covered  with  a  soft  undergrowth  of  fine 
down  which  is  an  objectionable  feature.  The  flower  is  yellow 
in  color  with  a  purplish  spot  at  the  base.  This  species  is  perhaps 
the  hardiest  of  the  cottons,  and  is  cultivated  over  a  wider 
range  of  latitude.!  It  forms  the  source  of  nearly  all  the  Indian 

being  long,  simple  or  stellate,  horizontal  or  spreading,  sometimes  short,  stellate, 
abundant,  or  the  plants  may  be  hirsute,  silky,  or  all  pubescence  may  be  more 
or  less  wanting,  the  plants  being  glabrous  or  nearly  so.  Glands  more  or  less 
prominent.  Stems  terete,  or  somewhat  angular  above,  branching.  Branches 
spreading  or  erect.  Leaves  alternate,  petioled,  the  petioles  about  equalling  the 
blades,  cordate  or  subcordate,  3-  to  5-,  rarely  y-lobed.  Lobes  from  oval  to  ovate, 
acuminate,  pale  green  above,  lighter  beneath,  mere  or  less  hairy  on  the  vein, 
3-  to  5-  or  7-veined,  the  midvein  and  sometimes  the  nearest  lateral  veins  glandular 
towards  the  base  or  glands  wanting.  Sinus  obtuse.  Lower  leaves  sometimes 
cordate,  acuminate,  entire,  or  slightly  lobed.  Stipules  erect  or  spreading,  ovate- 
lanceolate  to  linear-lanceolate,  acuminate,  entire,  or  occasionally  somewhat 
dentate.  Peduncles  erect  in  flower,  becoming  pendulous  in  fruit.  Involucre  3-, 
rarely  4-parted,  shorter  than  the  corolla,  appressed,  spreading  in  fruit,  broadly 
cordate,  incisely  serrate,  the  divisions  lanceolate-acuminate,  entire  or  sometimes 
sparingly  dentate.  Calyx  less  than  half  the  length  of  the  involucre  cup-shaped, 
dentate,  with  short  teeth.  Petals  erect,  spreading  obovate  or  cuneate,  obtuse  or 
emarginate,  curled  or  crenulate,  white  or  pale  yellow,  usually  with  a  purple  spot 
near  the  base,  in  age  becoming  reddish.  Stamens  half  the  length  of  the  corolla. 
Pistil  equal  or  longer  than  the  stamens.  Ovary  rounded  obtuse  or  acute,  glandular, 
3-  to  5-celled.  Style  about  twice  the  length  of  the  ovary,  3-  to  5-parted  above, 
the  glandular  portion  often  marked  with  2  rows  of  glands.  Capsule  erect,  glo- 
bose or  ovate,  obtuse  or  acuminate,  mucronate,  pale  green,  3-  to  5-celled.  Valves 
ovate  to  oblong,  with  spreading  tips.  Seed  5  to  n  in  each  cell,  free,  obovate  to 
subglabrous,  narrowed  at  base,  clothed  with  two  forms  of  fibre,  one  short  and 
dense,  closely  enveloping  the  seed,  the  other  2  to  3  times  the  length  of  the  seed, 
white,  silky,  and  separating  with  some  difficulty.  Cotyledons  somewhat  glandular, 
punctate. 

*  Parlatore  claims  that  this  species  originated  in  India,  while  Todaro  says 
that  it  is  spontaneous  in  Asia  and  perhaps  also  in  Egypt,  and  that  G.  ivightianum 
is  the  primitive  form  of  the  Indian  cottons;  others  still  consider  it  as  a  native 
of  Africa.  According  to  Bulletin  No.  33  (U.  S.  Dept.  Agric.),  it  is  probable  that 
G.  hcrbaceum  is  not  a  definite  species,  but  has  been  developed  by  cultivation 
from  perhaps  several  wild  species,  and  it  represents  not  a  species  but  a  group  of 
hybrids  and  forms  more  or  less  closely  related. 

f  The  following  species  are  considered  as  synonyms  of  G.  herbaceum:  G.  album 
Ham.,  G.  chinense  Fisch.,  G.  croceum  Ham.,  G.  eglandtdosum  Cav.,  G.  elatum 
Salis.,  G.  glandulosum  Steud.,  G.  hirsutum  Linn.,  G.  indicum  Lam.,  G.  latifolium 
Murr.,  G.  leoninum  Medic.,  G.  macedonicum  Murr.,  G.  micranthum  Cav.,  G.  molle 


210  THE  TEXTILE  FIBRES 

cotton,*  as  well  as  the  buff-colored  Nankin  cotton  of  China, 
and  the  short-stapled  varieties  of  Egyptian  and  Smyrna  cottons. 
It  is  used  for  the  spinning  of  low-count  yarns,  also  for  the  mak- 
ing of  condenser  yarns  for  the  manufacture  of  flannelettes.f 
(3)  G.  hirsutum'l,  including  most  of  the  cotton  from  the 

Mauri,  G.  nanking  Meyen,  G.  obtusifolium  Roxb.,  G.  paniculalum  Blanco,  G.  punc- 
tatum  Guil.,  G.  religiosum  Linn.,  G.  siamense  Tenore,  G.  sinense  Fisch.,  G.  stric- 
tum  Medic.,  G.  tricuspidatum  Lam.,  and  G.  vitifolium  Roxb. 

*  Todaro  claims  that  the  species  G.  wightianum  is  the  form  chiefly  cultivated 
in  India.  It  differs  from  the  general  form  of  G.  herbaceum  in  that  the  latter  has 
broader  and  more  rounded  leaves,  and  broader,  thinner,  and  deeper  cut  brac- 
teoles.  The  botany  of  G.  wightianum  is  as  follows:  Stems  erect,  somewhat 
hairy,  branches  spreading  and  ascending.  Leaves,  when  young,  densely  covered 
with  short  thick,  stellate  hairs,  becoming  nearly  glabrate  in  age;  ovate-rotund, 
scarcely  cordate,  3-  to  5-,  rarely  7-lobed;  lobes  ovate,  oblong,  acute,  constricted 
at  base  into  a  rounded  sinus.  Stipules  on  the  peduncles  almost  ovate,  others 
linear-lanceolate,  acuminate.  Flowers  yellow  with  a  deep  purple  spot  at  base, 
becoming  reddish  on  the  outside  in  age.  Bracteoles  small,  slightly  united  at 
base,  ovate,  cordate,  acute,  shortly  toothed.  Peduncles  erect  in  flower,  recurved 
in  fruit,  one-quarter  the  length  of  the  petioles.  Capsule  small,  ovate,  acute, 
4-celled,  with  8  seeds  in  each  cell.  Seeds  small,  ovate,  subrotund,  clothed  with 
two  forms  of  fibre,  the  inner  short  and  closely  adhering,  the  other  longer,  white 
or  reddish. 

There  is  another  very  similar  form  indigenous  to  India  known  as  G.  neglectum, 
it  grows  as  a  large  bush,  and  its  fibre  constitutes  the  majority  of  the  commer- 
cial Bengal  cotton.  Its  botany  is  as  follows:  Stem  erect.  Branches  slender, 
graceful,  spreading.  Leaves,  lower  ones  5  to  7  palmately  lobed,  segments  lanceo- 
late, acute,  rarely  bristle-tipped,  sinus  rounded,  the  small  lobes  in  the  sinuses 
less  distinct  than  in  G.  arboreum,  upper  leaves,  3-parted.  Stipules  next  the  ped- 
uncles semiovate,  dentate,  the  others  linear-lanceolate,  acute.  Peduncles,  with 
short  lateral  branches,  2  to  4  flowered.  Involucrat  bracts  coalescent  at  base, 
deeply  and  acutely  laciniate.  Petals  less  than  twice  the  length  of  the  involucral 
bracts,  obovate,  unequally  cuneate,  yellow,  with  a  deep  purple  spot  at  base. 
Stamen-tube  half  the  length  of  the  corolla,  naked  at  base.  Capsule  small,  ovate, 
acute,  cells  5-  to  8-seeded,  seed  obovate,  small,  clothed  with  two  forms  of  fibre, 
one  very  short,  closely  adherent,  and  of  an  ashy  green  color,  the  other  longer, 
rather  harsh,  white. 

t  Notwithstanding  the  inferiority  of  Indian  to  American  cotton,  the  Dacca 
spinners  can  to-day  produce  from  what  is  considered  a  very  poor-  cotton  staple  a 
yarn  quite  as  fine  as  that  made  in  England  and  America  from  the  finest  and  best 
staples.  This  remains  one  of  the  enigmas  of  the  cotton  industry,  and  it  would 
seem  that  the  hand  spinners  can  accomplish  something  the  machine  spinners 
cannot. 

J  Under  cultivation  this  plant  varies  in  many  directions.  It  is  usually  a  coarse, 
stunted,  much-branched,  erect,  greenish  red,  dust-coated  bush  (this  peculiarity 
being  a  consequence  of  the  abundance,  length,  and  strength  of  the  hairs  with  which 


COTTON  211 

southern  United  States*  also  known  as  upland  or  peeler  cotton,  f 
The  plant  is  shrubby  in  appearance,  seldom  reaching  more  than 
7  feet  in  height;  like  the  preceding  variety,  the  seeds  are  also 
covered  with  a  fine  undergrowth  of  down.  The  flower  is  either 
yellowish  white  or  of  a  faint  primose  tint. 

Todaro  claims  that  this  species  originated  in  Mexico,  whence 
it  has  been  spread  by  cultivation  throughout  the  warmer  por- 
tions of  the  world;  to  this  form  he  also  ascribes  the  Georgia 
or  long-stapled  upland  cotton.  Parlatore,  on  the  other  hand, 
considers  it  as  indigenous  to  the  islands  in  the  Gulf  of  Mexico 
as  well  as  the  mainland,  and  that  all  green-seeded  cotton, 
wherever  cultivated,  originated  from  this  form. 

(4)  G.  arboreum^  including  the  cotton  from  Ceylon,  Arabia, 

the  leaf  stalks,  etc.,  are  covered).  The  leaves  rapidly  lose  the  habit  of  being  entire, 
and  are  mostly  3-lobed,  or  as  a  result  of  luxuriant  cultivation,  become  partially 
lobed.  The  flowers  range  from  small  pale  yellow  to  large  and  yellow  with  a 
purplish  tinge.  The  fruit  is  usually  4-celled,  and  the  seeds  always  large,  ovate, 
truncate  on  one  extremity,  and  with  a  pronounced  fuzz,  which  may  be  grayish, 
rusty  or  green  in  color  (see  Watt,  Wild  and  Cultivated  Cottons,  pp.  183,  184). 

*  American  or  mainland  cotton  is  the  typical  cotton  of  the  world.  It  is  grown 
in  the  American  cotton  belt  which  extends  from  southeast  Virginia  to  Texas. 
This  cotton  is  suited  for  all  numbers  of  yarn  up  to  50*5  warp  and  8o's  filling, 
being  clean,  regular  in  length  of  staple  and  well  graded.  On  account  of  these 
features,  as  well  as  the  fact  that  the  quantity  raised  is  greater  than  all  the  other 
cotton  of  the  world,  the  price  of  American  cotton  regulates  the  price  of  cotton 
throughout  the  world.  Of  this  American  cotton,  the  Gulf  (New  Orleans),  Benders, 
or  Bottom  Land  varieties  are  the  most  important,  varying  in  length  from  i  to 
1 1  inches.  Cotton  sold  in  the  market  as  Mobile,  Peelers,  and  Allan-seed  belong 
to  the  same  variety  and  are  next  in  importance;  while  Mississippi,  Louisiana, 
Selina,  Arkansas,  and  Memphis  cottons  are  slightly  inferior.  Texas  cotton  varies 
from  |  to  i  inch  in  length  and  is  suitable  for  warp  yarns  up  to  32's.  Next  in 
importance  is  the  upland  cotton,  having  a  length  of  £  to  i  inch  and  suitable  for 
spinning  into  3o's  filling.  Cottons  sold  under  the  names  of  Georgia,  Boweds, 
Norfolk,  and  Savannah  also  belong  to  the  upland  variety. 

t  The  cotton  plant  of  the  Southern  States  is  a  small  annual  shrub  from  2  to 
4  feet  in  height,  always  branching  extensively.  The  limbs  are  longest  at  the 
bottom  of  the  stalk,  and  short  and  light  at  the  top.  The  flowers  are  white  or 
pale  yellow  or  cream-colored  the  first  day,  becoming  darker  and  redder  the  second 
day,  and  fall  to  the  ground  on  the  third  or  fourth  day,  leaving  a  tiny  boll  developed 
in  the  calyx.  This  boll  enlarges  until  maturity  when  it  is  not  unlike  the  size  and 
shape  of  a  hen's  egg.  When  matured,  the  boll  cracks  and  opens  the  three  to 
six  compartments  which  hold  the  seed  and  the  lint.  (Burkett,  Cotton,  p.  79.) 

t  The  descriptive  botany  of  this  species  is  as  follows:  Shrubby,  perennial,  but 


212  THE  TEXTILE   FIBRES 

etc.  As  the  name  indicates,  it  is  a  tree-like  plant,  and  grows 
from  12  to  1 8  feet  in  height.  The  fibres  are  of  a  greenish  color 
and  very  coarse;  its  flowers  are  of  a  purple  color.*  It  is 
commonly  known  as  tree  cotton  or  cotton  tree.  In  India  its  cul- 
tivation is  probably  more  ancient  than  that  of  any  other  cotton. 

(5)  G.  peruvianuw,    including    the    native    Peruvian    and 
Brazilian  cottons.     This  differs   from  other  varieties  of  cotton 
in  that  it  is  a  perennial  plant;   the  growth  from  the  second  and 
third  years,  only,  however,  is  utilized. 

(6)  G.  tahitense,  found  chiefly  in  Tahiti  and  other  Pacific 
islands. 

in  cultivation  sometimes  annual  or  biennial;  tomentose,  with  two  forms  of  hairs, 
one  long  and  simple,  the  other  more  numerous,  shorter,  and  xStellate;  glands 
small,  scarcely  prominent,  more  or  less  scattered.  Stem  erect,  terete,  very  branch- 
ing. Branches  speading,  terete.  Leaves  alternate,  petiolate,  with  petioles  a 
little  shorter  than  the  blade,  subcordate,  5-  to  y-lobed,  lobes  oblong-lanceolate 
or  lanceolate-acuminate,  bristle- tipped,  scarcely  channelled  above;  sinus  obtuse, 
often  with  a  small  lobe  in  some  of  the  sinuses,  beneath  pale  green  and  softly  pubes- 
cent, 5-  to  7-veined,  the  midvein  and  often  the  two  adjacent  ones  with  a  reddish- 
yellow  gland  near  their  base;  upper  leaves  palmately  3-  to  5-lobed,  lobes  short. 
Stipules  erect,  spreading,  lanceolate-acuminate.  Peduncles  axillary,  erect  before 
and  spreading  or  horizontal  after  flowering  and  drooping  in  fruit,  about  three- 
fourths  the  length  of  the  petioles,  terete,  destitute  of  glands,  i  to  2  usually 
i-flowered,  jointed  above  the  middle,  bearing  a  small  leaf  and  two  stipules  at 
this  point.  Involucre  three-parted,  appressed  or  scarcely  spreading  at  summit, 
many  nerved,  broadly  and  deeply  cordate,  ovate-acuminate,  5  to  9,  rarely  3 
dentate  or  nearly  entire.  Calyx  much  shorter  than  the  bracts,  subglobose, 
truncate,  crenulate  or  subdentate,  with  a  large  gland  at  the  base  within  the 
involucre.  Corolla  campanulate,  petals  erect,  or  spreading  broadly  cuneate, 
subtruncate,  crisp  or  crenulate,  purple  or  rose-colored,  with  a  large  dark  purple 
spot  at  the  base.  Staminal  tube  about  half  the  length  of  the  corolla.  Pistils 
equally  or  a  little  longer  than  the  stamens.  Ovary  ovate,  acute,  glandular, 
usually  3-celled.  Style  a  little  longer  than  the  ovary,  3-parted  without  glands. 
Capsule  pendulous,  a  little  longer  than  the  persistent  involucre,  ovate,  rounded, 
glandular,  3-  to  4-celled,  and  valved.  Valves  ovate,  oval,  spreading,  mucronate- 
acuminate,  the  mucro  recurved.  Seed  5  to  6,  ovate,  obscurely  angled,  black. 
Fibre  two  forms,  one  white,  long,  overlying  a  dark  green  or  black  down;  not 
readily  separable  from  the  seed. 

*  A  synonym  of  this  species  is  G.  religiosum;  it  appears  to  be  indigenous  to 
India.  The  plant  is  perennial  and  lasts  from  five  to  six  years,  and  though  the 
fibre  is  fine,  silky,  and  of  good  length,  yet  there  is  but  little  of  it  produced.  No 
varieties  of  this  species  are  grown  in  America  for  commercial  purposes,  and  not 
even  in  India,  where  it  is  principally  cultivated,  is  it  a  very  valuable  type  of 
cotton;  it  is  never  used  as  a  field  crop. 


COTTON  213 

(7)  G.  sandwichense,  occurring  principally  in  the  Hawaiian 
Islands. 

This  classification  is  claimed  to  include  all  the  commercial 
varieties  of  cotton;  it  is  probable,  however,  that  the  last  two 
can  be  included  under  the  barbadense  and  hirsutum  varieties, 
as  they  possess  the  same  characteristics  as  these  fibres. 

Dr.  Royle  reduces  the  number  of  species  of  the  cotton 
plant  to  the  following  four: 

(1)  Gossypium  arbor  cum. 

(2)  herbaceum. 

(3)  barbadense. 

(4)  hirsutum. 

Other  authorities  on  the  botany  of  the  cotton  plant  have 
recognized  many  more  species  than  those  above  described. 
Agostino  Todaro  *  has  described  52  varieties,  while  the  Index 
Kewensis  records  42  distinct  species  and  refers  to  88  others 
which  it  classifies  as  synonyms.  Hamilton  reduces  the  number 
of  species  to  three,  namely,  the  white-seeded,  black-seeded,  and 
yellow-linted,  assigning  to  these  species  the  botanical  names 
album,  nigrum,  and  croceum.  The  chief  difficulty  experienced 
in  the  botanical  classification  of  the  cotton  plant  is  the  fact 
that  it  hybridizes  f  very  readily  and  has  a  tendency  to  suffer 

*  Rel.  sulla  coltura  del  cotoni  in  Italia,  1877-78,  vol.  2,  pp.  1057  and  1058. 

f  Bulletin  No.  33  (vide  supra)  makes  the  following  remarks  relative  to  the 
subject  of  the  cross-fertilization  of  cotton.  The  flower  of  the  cotton  plant  is  so 
large  and  develops  so  rapidly  that  cross-fertilization  is  easily  secured.  Flowers 
which  are  to  be  fertilized  should  be  among  those  which  are  developed  early  in  the 
season,  and  should  always  be  those  on  healthy  and  vigorous  plants.  The  flowers 
to  be  operated  upon  should  be  selected  late  in  the  afternoon;  one  side  of  the 
unopened  bud  should  be  split  lengthwise  with  a  sharp  knife  having  a  slender 
blade,  and  the  stamens  removed.  The  anthers,  the  fertilizing  parts  of  the 
stamens,  will  be  found  well  developed  and  standing  well  away  from  the  pistil, 
though  not  yet  so  matured  as  to  be  discharging  pollen.  These  can  be  readily 
separated  from  their  support  by  a  few  careful  strokes  of  the  knife,  and  the  emascu- 
lated flower  should  then  be  enclosed  in  a  paper  bag  to  prevent  access  of  pollen 
from  unknown  sources.  The  following  morning  the  pistil  will  be  fully  developed 
and  ready  to  receive  pollen.  A  freshly  opened  flower  from  a  healthy  plant  of  the 
variety  which  it  is  desired  to  use  in  making  the  cross  is  picked  and  carried  to 
the  plant  which  was  treated  the  previous  evening,  the  bag  is  removed  from  the 


214  THE  TEXTILE  FIBRES 

alteration  in  variety  with  change  in  the  conditions  of  its  cultiva- 
tion or  variation  in  the  character  of  the  soil  or  climate. 

In  Europe  cottons  are  graded  according  to  their  value  as 
follows : 

1.  Long  Georgia.       4.  Louisiana.  7.  Short  Georgia. 

2.  Makko  5.  Cayenne.  8.  Surat. 

3.  Pernambuco          6.  New  Orleans.        9.  Bengal. 

Besides  the  varieties  of  cotton  above  enumerated,  which  are 
practically  all  which  find  any  important  commercial  applica- 
tion, there  is  another  plant  which  yields  a  fibre  somewhat  similar 
to  cotton,  and  known  as  the  silk-cotton  plant.  It  belongs  to 
the  same  natural  order,  Malvacea,  as  the  ordinary  cotton  plant, 
but  is  of  a  different  genus,  being  Salmalia  instead  of  Gossypium. 
It  grows  principally  on  the  African  coast  and  in  some  parts  of 
tropical  Asia.  The  plant  is  rather  a  large  tree,  reaching  from 
70  to  80  feet  in  height.  The  blossoms  are  red  in  color,  and  the 
seeds  are  covered  with  long  silky  fibres,  which  are  not  adapted, 
however,  for  spinning. 

Although  fibres  from  the  different  species  of  the  cotton 
plant  all  possess  the  same  general  physical  appearance,  never- 
theless, there  are  characteristic  features  in  each  worthy  of 
careful  observation.  Though  to  the  casual  observer  the 
different  varieties  of  cotton  fibre  look  mpre  or  less  alike,  there 
is  nevertheless  great  differences  in  qualities  and  properties, 
and  these  must  be  carefully  recognized  by  the  manufacturer 
who  must  select  and  grade  his  stock  with  reference  to  the 
nature  of  the  yarn  he  is  to  spin.  It  requires  a  highly  trained 
and  experienced  judge  to  properly  grade  the  different  qualities 
'  of  cotton  for  manufacturing  purposes,  and  though  the  greater 
part  of  this  skill  is  acquired  through  intimate  contact  with 
actual  manufacturing  conditions,  yet  great  aid  may  be  had 
through  the  use  of  the  microscope  in  scientifically  studying 
the  structure  of  the  cotton  fibre. 

prepared  flower,  and  by  means  of  a  camel's-hair  brush  pollen  is  dusted  over  the 
end  and  upper  part  of  the  pistil.  The  paper  bag  is  then  replaced  and  allowed 
to  remain  two  days,  after  which  it  should  be  removed. 


COTTON  215 

Sea-island  Cotton. — This  constitutes  the  most  valuable 
perhaps,  of  all  the  different  species.  Its  chief  points  of 
superiority  are  (a)  its  length,  being  more  than  half  an  inch 
longer  than  the  average  of  other  cottons;  (b)  its  fineness  of 
staple;  (c)  its  strength;  (d)  its  number  and  uniformity  of 
twists,  which  allow  it  to  be  spun  to  finer  yarns;  (e)  its  appear- 
ance, it  being  quite  soft  and  silky.  It  is  also  characterized 
by  a  light-cream  color.  Sea-island  cotton  is  mostly  used  for 


FIG.  59. — Sea-island  Cotton.     (X4oo).     (Micrograph  by  author.) 

the  production  of  fine  yarns  ranging  from  i2o's  to  300*3;*  it 
is  said  that  as  fine  as  2ooo's  has  been  spun  from  it.f  On 
account  of  its  adaptability  for  mercerizing  it  is  also  largely 
employed  for  this  purpose,  in  which  case  much  coarser  yarns 

*  The  "count"  of  cotton  yarn  means  the  number  of  hanks  of  840  yards  each 
contained  in  i  Ib.  The  size  i2o's,  for  instance,  means  cotton  yarn  of  such 
fineness  that  120  hanks  of  840  yards  (  =  100,800  yards)  weigh  i  Ib.  (see  p.  579). 

t  See  Monie,  Structure  of  the  Cotton  Fibre,  p.  40,  as  authority  for  this  state- 
ment. A  thread  of  such  fineness  would  not  be  commercial,  and  has  never  been 
prepared,  except,  perhaps,  in  an  experimental  manner. 


216  THE  TEXTILE  FIBRES 

are  often  prepared  from  it.  Owing  to  the  wide  cultivation  of 
sea-island  cotton  at  the  present  time,  for  its  growth  is  no  longer 
strictly  confined  to  the  islands  of  the  sea,*  it  is  difficult  to  make 
a  definite  statement  as  to  its  length  of  staple,  as  this  will  vary 
considerably  with  the  method  and  place  of  cultivation.!  The 
maximum  length,  however,  may  be  taken  as  2  inches,  and  the 
minimum  as  if  inches,  with  a  mean  of  if  inches.  Sea-island 
cotton  gives  a  smaller  yield  of  fibre  than  any  variety  of  cotton 
grown  in  America,  but,  on  account  of  the  greater  length  and 
fineness  of  staple,  it  has  a  much  higher  market  value.  The 
average  yield  is  about  100  Ibs.  of  lint  per  acre,  and  it  requires 
from  3^  to  4^  Ibs.  of  seed  to  yield  i  Ib.  of  lint.  The  actual 
cost  of  growing  is  said  to  be  from  23  to  26  cts.  per  Ib.  of  lint. 
A  normal  crop  for  the  area  in  which  it  is  grown  is  from  90,000 
to  110,000  bales,  nine-tenths  of  which  is  grown  in  Georgia  and 
Florida.  In  the  limited  area  in  which  it  is  produced  probably 
500,000  bales  could  be  grown.  Florida  sea-island  cotton 
is  very  similar  in  general  characteristics  to  sea-island  proper, 
possessing  about  the  same  mean  length  of  staple,  but  being 
somewhat  less  in  the  maximum  length.  Both  of  these  varieties 

*  Some  writers  claim  that  sea-island  cotton  is  peculiarly  of  American  origin; 
that  it  was  found  on  the  island  of  San  Salvador  by  Columbus,  and  by  him  brought 
to  Spain.  Other  writers,  among  whom  is  Masters  (Jour.  Linn.  Soc.,  vol.  19, 
p.  213),  assert  that  this  cotton  is  of  central  African  origin.  Sea-island  was  intro- 
duced into  the  United  States  in  1786,  and  was  first  grown  on  St.  Simons  Island 
off  the  coast  of  Georgia.  It  appears  to  have  been  brought  from  the  island  of 
Angulla  in  the  Carribean  Sea  to  the  Bahamas,  and  from  the  latter  to  the  coast 
of  Georgia.  From  St.  Simons  the  plant  extended  to  the  Sea  Islands  of  Charleston, 
where  the  finest  varieties  are  now  grown.  Very  fine  staple  is  also  grown  along 
the  coast  of  East  Florida. 

f  Sea-island  cotton  may  be  cultivated  in  any  region  adapted  to  the  olive  and 
near  the  sea,  the  principal  requisite  being  a  hot  and  humid  atmosphere,  but  the 
results  of  acclimatization  indicate  that  the  humid  atmosphere  is  not  entirely 
necessary  if  irrigation  be  employed,  as  this  species  is  undoubtedly  grown  exten- 
sively in  Egypt.  As  a  rule,  the  quality  of  the  staple  increases  with  the  proximity 
to  the  sea;  but  there  are  exceptions  to  this  rule,  as  that  grown  on  Jamaica  and 
some  islands  is  of  rather  low  grade,  while  the  best  fibre  is  produced  along  the 
shores  of  Georgia  and  Carolina.  (Bulletin  No.  33,  U.  S.  Dept.  Agric.)  Sea-island 
requires  a  great  deal  more  moisture  than  the  upland  cottons;  in  fact,  moisture  is 
an  all-important  factor  in  the  quality  of  the  staple.  Dry  years  give  a  poor  staple 
and  wet  years  a  good  staple. 


COTTON  217 

of  sea-island  show  a  maximum  diameter  of  0.000714  inch, 
a  minimum  of  0.000625  inch,  and  a  mean  of  0.000635  inch. 
Fiji  sea-island  is  less  regular  in  its  properties  than  the  two 
preceding  varieties,  and  though  its  maximum  length  is  some- 
what greater  than  sea-island  itself,  yet  the  mean  length  is 
about  the  same,  as  is  also  the  diameter.  This  cotton,  how- 
ever, has  a  very  irregular  staple  and  contains  a  large  per- 
centage of  imperfect  fibres,  which  causes  the  waste  to  be  rather 
high.  The  number  of  twists  in  the  fibre  is  also  less  and  does 
not  occur  as  regularly.  Gallini  Egyptian  is  sea-island  cotton 
grown  in  Egypt.*  It  is  somewhat  inferior  to  the  American 
varieties  in  general  properties.  It  possesses  a  yellowish 
color,  which  distinguishes  it  from  the  product  of  all  other 
countries.  Gallini  cotton  has  the  bad  feature  of  containing 
considerable  undeveloped  and  short  fibre,  and  this  somewhat 
lessens  its  commercial  value.  Peruvian  sea-island  also  possesses 
this  same  defect,  but,  in  addition,  contains  usually  quite  a 
large  amount  of  foreign  matter,  such  as  broken  leaf,  sand,  seed 
particles,  etc.  The  maximum  length  of  the  fibre  is  if  inches, 
the  minimum  if  inches,  and  the  mean  ij  inches.  The  fibres 
differ  very  little  in  their  diameter,  the  average  being  0.000675 
inch.  Peruvian  sea-island  is  somewhat  coarser  in  structure  than 
the  sea-island  proper,  being  more  hairy  in  appearance;  it  has  a 
slight  golden  tint.  In  staple  it  varies  from  if  inches  in  length 
to  if  inches,  with  a  mean  of  ij  inches.  Tahiti  sea-island 
resembles  the  Fiji  variety  very  closely;  it  has  a  creamy  color. 
The  length  of  staple  varies  from  i  f  to  if  inches,  with  a  mean 
of  ij  inches.  It  shows  a  considerable  percentage  of  imperfect 
fibres  due  to  a  short  undergrowth  on  the  seed.  Its  average 
diameter  is  0.000641  inch. 

Gossypium  herbaceum. — This  variety  is  of  Asiatic  origin, 
and  its  botanical  name  describes  the  character  of  its  growth. 

*  The  Bahmia  variety  of  Egyptian  cotton  is  a  form  of  sea-island  cotton  to  which 
Todaro  has  given  the  varietal  name  of  polycarpum.  It  is  characterized  by  numer- 
ous flowers  springing  from  a  single  axil,  and  an  erect,  slightly  branching  habit, 
hence  giving  a  large  yield  per  acre.  It  was  once  thought  that  the  Bahmia  cotton 
was  a  hybrid  between  okra  and  cotton,  but  in  a  Kew  Report  (1887,  p.  26)  this 
is  shown  to  be  incorrect. 


218  THE  TEXTILE   FIBRES 

India  is  supposed  to  be  the  original  home  of  the  herbaceous 
type,  but  it  has  spread  extensively  through  China,  Arabia, 
Persia,  and  Africa.  The  vine  cotton  of  Cuba  belongs  to  this 
species,  and  is  peculiar  because  of  its  large  pods  and  excessive 
number  of  seeds.  The  long  staple  upland  cotton  of  America 
also  belongs  to  this  species. 

The  cultivated  cottons  of  to-day  are  far  different  from  the 
original  form  of  the  G.  herbaceum,  which  gave  only  28  to  29  per 
cent  of  fibre,  with  a  staple  20  to  30  mm.  long.  The  proportion 
of  fibre  has  been  greatly  increased,  reaching  as  high  as  36  and 
even  40  per  cent  in  some  varieties,  while  the  length  of  staple 
has  increased  correspondingly,  sometimes  reaching  fully  three 
times  its  original  length. 

Smyrna  cotton  is  grown  principally  in  Asiatic  Turkey. 
It  has  a  rather  characteristic  appearance  under  the  microscope, 
being  very  even  in  its  diameter  but  irregular  in  its  twist,  show- 
ing many  fibres  where  the  twist  is  almost  entirely  absent. 
In  length  the  staple  varies  from  £  to  ij  inches,  with  a  mean  of 
i  inch;  the  mean  diameter  is  about  0.00077  inch. 

The  first  variety  of  cotton  to  be  cultivated  in  Egypt  was 
called  Makko-Jumel;  this  went  through  many  changes  and 
evolutions,  and  gradually  changed  its  color  to  a  yellowish 
brown,  the  new  variety  being  known  as  Ashmouni,  from  the 
valley  of  Ashmoun,  where  the  change  was  first  noticed.  The 
principal  varieties  of  Egyptian  cotton  now  grown  are  the 
Mitafifi,  Ashmouni,  Bamia,  Abbasi,  Jannovitch  and  Gallini. 
Formerly  the  Ashmouni  formed  the  bulk  of  the  Egyptian 
crop,  but  it  is  now  largely  superseded  by  the  Mitafifi,  Abassi, 
Yannovitz  and  Unbarri.  Mitafifi  is  the  chief  product  of  lower 
Egypt,  while  upper  Egypt  grows  Ashmouni  almost  exclusively. 
In  color  the  Ashmouni  is  a  light  brown,  and  its  staple  is  over 
an  inch  in  length.  The  Mitafifi  cotton  is  said  to  have  been 
discovered  by  a  Greek  merchant  in  a  village  of  that  name; 
it  is  characterized  by  the  seed  having  a  bluish  green  tuft  at 
the  extremity.  Its  color  is  a  richer  and  darker  brown  than  the 
Ashmouni;  the  fibre  is  long,  strong,  and  fine,  and  very  desirable 
in  the  market.  The  plant  withstands  drought  and  attacks 


COTTON  219 

by  worms  better  than  any  other  variety.  It  also  requires 
less  attention  for  picking  and  gives  a  better  output  in  ginning. 
The  Bahmia  cotton  is  the  next  most  extensively  cultivated; 
the  fibre  is  poor  compared  with  the  foregoing,  being  light  brown 
in  color  and  not  very  strong.  The  Abbasi  cotton  is  of  rather 
recent  introduction  being  produced  in  1895  by  a  Greek  named 
Parahimona  who  named  it  after  the  Khedive  of  Egypt.  It 
appears  to  have  sprung  from  imported  seed.  The  fibre  is 
white,  and  is  longer  and  more  silky  than  Mitafifi,  though  not 
so  strong.  The  Yannovitz  variety  is  named  from  the  Greek 
who  produced  it.  It  is  one  of  the  best  existing  qualities  in 
Egypt,  the  fibre  being  long,  strong,  and  silky  and  commanding 
a  high  market  price.  The  Unbarri  is  the  most  recent  variety 
of  Egyptian  growths;  its  color  is  lighter  than  Mitafifi.  The 
Sultdin  is  a  very  long  and  silky  variety,  resembling  sea-island 
cotton.  It  is  an  expensive  cotton  to  grow  and  is  limited  in 
amount.  The  Gallini  cotton  was  derived  from  sea-island, 
but  it  has  almost  entirely  disappeared  from  cultivation,  as 
its  quality  has  greatly  deteriorated.  Egyptian  cotton,*  as  a 
class,  is  not  so  fine  as  sea-island,  but  is  better  than  American 
upland  cotton,  that  is,  for  goods  requiring  a  smooth  finish  f 
and  a  high  lustre,  the  staple  being  strong  and  silky.  { 

*  The  fibre  of  Egyptian  cotton  is  especially  adapted  to  the  manufacture  of 
hosiery  yarns  and  yarns  for  mercerizing.  The  United  States  imports  Egyptian 
cotton  to  the  value  of  about  $10,000,000  per  year.  The  total  annual  crop  of 
cotton  from  Egyptian  plantations  is  from  850,000  to  875,000  bales. 

f  The  silky  nature  of  the  Egyptian  cottons,  and  the  fact  that  they  possess  a 
brown  color,  probably  indicate  that  they  are  really  of  sea-island  origin,  but  there 
is  no  evidence  to  show  whence  their  deeper  coloration  than  sea-island  arose, 
unless  it  was  by  means  of  a  cross  with  some  highly  colored  variety  such  as  Peruvian. 
It  has  been  suggested  that  the  peculiar  soil  conditions  of  Egypt  may  account 
for  the  color,  but  there  exists  in  Egypt  a  pure  white  variety,  abassi,  which  shows 
no  tendency  whatever  toward  the  development  of  a  brown  coloration,  which 
seems  to  preclude  this  idea.  (Bull.  62,  U.  S.  Dept.  Agric.) 

tMany  of  the  Egyptian  cottons  are  hybrids  of  G.  braziliense,  such  as  the 
Ashmouni,  Mitafifi,  Zafiri,  and  Abassi.  It  is  probable,  however,  that  the 
Ashmouni  as  described  by  some  writers  is  G.  microcarpum.  The  Abassi  cotton 
is  known  in  commerce  as  white  Egyptian.  It  is  the  only  white  cotton  now  grown 
in  Egypt,  and  it  made  its  appearance  there  in  1891-92.  Ashmouni  cotton  is  the 
oldest  variety  of  Egyptian  cotton;  its  cultivation  was  at  one  time  general  in  the 
Delta,  but  it  is  now  practically  confined  to  Upper  Egypt.  It  differs  from  other 


220  THE  TEXTILE  FIBRES 

Brown  Egyptian  cotton  is  supposed  to  be  indigenous  to  that 
country.  It  is  characterized  by  a  fine  golden  color,  and  great 
toughness  and  tensile  strength.*  It  is,  however,  shorter  and 
coarser  than  the  Mitafifi  cotton.  In  length  of  staple  it  varies 
from  ij  to  1 1  inches,  with  a  mean  of  ij  inches;  the  mean 
diameter  is  0.000738  inch.f 

African  cottons  are  all  derived  from  the  herbaceum  species. J 
These  cottons  have  a  slight  brownish  tint,  and  always  contain  a 
large  amount  of  short  fibres.  The  fibres  also  vary  much  in  diame- 
ter and  thickness  of  the  tube-walls,  and  many  exhibit  a  transpar- 
ent appearance  under  the  microscope.  Yarns  made  from  these 
cottons  are  always  uneven  on  the  surface.  The  length  of  staple 
varies  from  £  to  ij  inches,  with  an  average  of  i  inch;  the  mean 
diameter  is  0.00082  inch.  Hingunghat  cottons  are  Indian  vari- 
eties; the  quality  of  these  varies  with  the  soil  and  climate  of  the 
province  in  which  they  are  grown.  §  As  a  rule,  they  are  of  rather 

forms  of  Egyptian  cotton  in  that  its  seed  is  clean,  that  is,  possesses  no  adhering 
fibre.  Mitafifi  is  the  principal  cotton  grown  in  Egypt.  It  takes  its  name  from 
a  village  where  it  was  first  grown  in  1883.  Its  price  forms  the  basis  of  that  of 
other  varieties  of  Egyptian  cotton.  Its  fibre  is  brownish  in  color,  long,  and  lus- 
trous, high  in  tensile  strength  and  silky  to  the  touch.  In  length  it  reaches  if 
to  1 1  inches.  Mitafifi  cotton  has  replaced  many  of  the  older  varieties,  principal 
among  which  was  that  known  as  Bahmia  cotton.  Jannovitch  cotton  is  the  finest 
and  most  silky  of  all  Egyptian  varieties.  Its  cultivation  dates  back  only  a 
few  years.  Its  staple  reaches  i£  to  it  inches  in  length  and  is  very  strong.  It 
is  supposed  to  have  originated  from  a  cross  of  good  Gallini  and  Mitafifi.  There 
have  been  attempts  to  grow  sea-island  cotton  in  Egypt,  and  though  the  first  year's 
crop  is  excellent,  that  of  the  second  and  third  year  shows  rapid  deterioration. 

*  Egyptian  cotton,  on  account  of  its  long,  strong  and  silky  staple,  is  especially 
adapted  for  sewing-thread,  fine  underwear,  and  hosiery,  and  other  goods  requir- 
ing a  smooth  finish  and  high  lustre. 

f  It  is  interesting  to  note  that  yarn  of  Egyptian  cotton  is  finer  than  that  of 
the  same  number  made  from  American  cotton.  The  fibres  of  the  former  are 
narrower,  which,  combined  with  their  great  flexibility,  permits  of  their  being 
closely  twisted  one  with  the  other,  thus  making  the  yarn  firmer  and  more  com- 
pact. (Hanausek,  The  Microscopy  of  Technical  Products,  p.  61.) 

J  Watt  is  of  the  opinion  that  G.  herbaceum  proper  does  not  occur  in  Africa, 
the  chief  cultivated  African  plants  being  derived  from  G.  obtusifolium  and  G. 
nankin,  variations  of  the  foregoing  species. 

§  Though  India  is  perhaps  the  oldest  of  the  cotton-producing  countries,  its 
yield  of  late  years  has  been  decreasing.  The  average  yield  per  acre  is  about 
one-half  the  average  American  yield;  for  though  the  soil  of  India  is  well  adapted 
to  cotton  growing,  the  climate  is  very  unfavorable. 


COTTON  221 

inferior  grade;  the  best  variety  is  the  Surat  cotton.*  Under  the 
microscope  the  Hingunghat  cotton  shows  much  variation  in  diam- 
eter, although  it  possesses  fewer  twists  than  the  better  grades 
of  cotton,  yet,  unlike  the  African  varieties,  it  shows  very  few 
fibres  without  any  convolutions  at  all.  In  length  of  staple 
it  varies  from  f  to  ij  inches,  with  a  mean  of  i  inch;  the  average 
diameter  is  0.00084  inch.  Broach,  Tinnevelly,  Dharwar,  Oomra- 
wuttee,  Dhollerah,  Western  Madras,  Complah,  Bengal,  and 
Scinde  are  other  varieties  of  Indian  cotton,  all  belonging  to  the 
herbaceum  species.  They  have  the  same  general  properties 
and  staple  as  the  preceding,  becoming  more  and  more  inferior, 
however,  in  the  order  of  the  list  given,  f 

Gossypium  hirsutum. — White  Egyptian,  unlike  the  brown 
variety  described  above,  is  not  indigenous,  but  was  transplanted 
from  America.  In  length  of  staple  it  varies  from  ij  to  if 
inches,  with  a  mean  of  ij  inches;  the  diameter  averages 
0.00077  inch.  This  cotton  shows  a  large  number  of  fibres 
having  but  partially  developed  spiral  twists.  Orleans  cotton 
is  the  typical  American  variety,  and  is  perhaps  the  best  of  the 
American  cottons.  J  The  fibres  are  quite  uniform  in  length, 
having  an  average  staple  of  about  i  inch  and  a  mean  diameter 
of  0.00076  inch.  It  is  almost  pure  white  in  color.  Texas 
cotton  much  resembles  the  foregoing,  but  has  a  slight  golden 
color;  its  length  and  diameter  of  staple  are  the  same.  Upland 
cotton  §  is  another  very  similar  variety;  its  length  of  staple, 

*  The  finest  sort  of  cotton  from  the  Orient  is  known  as  "Adenos." 

f  For  many  years  past  the  Indian  cotton  trade  has  been  drifting  into  a 
restricted  groove.  The  produce  goes  to  mills  which  do  not  require  a  superior 
or  long  staple,  but  one  which  is  uniform.  India  is  thus  destroyed  as  a  possible 
source  of  supply  for  the  English  mills.  The  Indian  mills  are  at  the  same  time 
compelled  to  look  to  foreign  countries  for  their  present  or  future  supplies  of 
superior  staples,  and  are  thus  more  or  less  confined  in  their  operation  to  one 
class  of  goods.  (See  Watt,  Wild  and  Cultivated  Cottons,  p.  200.) 

J  In  the  United  States  only  the  herbaceous  cottons  are  cultivated  to  any  extent; 
the  shrubby  and  arboreous  are  occasionally  grown  as  curiosities,  but  they  seldom 
or  never  produce  any  lint  in  regions  having  as  low  a  mean  temperature  as  the 
American  cotton  belt.  (Bulletin  No.  33,  U.  S.  Dept.  Agric.) 

§  There  is  considerable  difference  of  opinion  among  authors  when  discussing 
the  origin  of  upland  cotton.  The  weight  of  opinion  seems  to  be  that  the  species 
is  either  G.  herbaceum  or  G.  hirsutum,  which  many  consider  synonymous.  The 


222  THE  TEXTILE  FIBRES 

however,  is  somewhat  less  than  the  foregoing,  averaging  but 
xf  inch.  Its  twist  is  rather  inferior  to  the  Orleans,  and  it 
shows  a  larger  number  of  straight  fibres.  There  are  more 
than  a  hundred  recognized  horticultural  varieties  of  upland 
cotton  in  cultivation,  all  belonging  to  one  botanical  species 
G.  hirsutum,  native  to  the  American  tropics.  The  original 
wild  plants  in  the  tropical  zone  were  perennials,  but  the  plant 
is  cultivated  as  an  annual.*  Mobile  cotton  is  the  most  inferior 
of  the  American  varieties;  it  varies  in  length  of  staple  from 
|  to  i  inch,  with  a  mean  of  f  inch;  its  average  diameter  is 
0.00076  inch.  It  shows  about  the  same  microscopic  appearance 
as  upland  cotton.  Santos  cotton  comes  from  Brazil;  it  is  not 
much  in  demand  on  account  of  its  inferior  quality,  f 

Peruvian  Cotton. — Rough  Peruvian  cotton  J  has  a,  light 
creamy  color  and  is  rather  harsh  and  hairy  in  feel.§  Peruvian 

origin  of  this  species  is  much  more  confused  than  that  of  sea-island  cotton.  If 
we  would  separate  the  upland  cotton  into  two  species,  G.  herbaceum  and  G.  hir- 
sutum, probably  the  question  would  be  simplified,  as  the  former  is  generally 
considered  of  Asiatic  origin,  while  the  other  is  attributed  to  America.  (See 
Dodge,  Useful  Fibre  Plants,  p.  176.) 

*  Yearbook,  U.  S.  Dept.  Agric.,  1903. 

f  The  variety  known  as  G.  braziliense  is  a  representative  of  the  so-called 
"  kidney  cottons."  In  these  cottons  the  seeds  of  each  cell  are  loosely  adherent 
in  an  oval  mass,  whereas  in  the  other  varieties  of  cotton  the  seeds  are  free  from 
each  other.  G.  braziliense  is  an  arborescent  plant  with  very  large  5  to  7  divari- 
cate-lobed  leaves  and  very  deeply  laciniate  involucral  bracts.  The  Brazilian 
cottons  appearing  in  trade  under  the  names  Santos,  Ceara,  Pernambuco,  etc., 
do  not  seem  to  belong  to  G.  braziliense,  as  they  are  not  kidney  cottons;  they 
evidently  belong  to  the  G.  barbadense  and  G.  herbaceum  species. 

J  The  yield  of  native  Peruvian  is  very  high;  it  is  said  to  average  as  much 
as  625  Ibs.  per  acre. 

§  Owing  to  the  fact  that  the  fibre  closely  resembles  wool  in  appearance  and 
quality,  almost  the  entire  crop  of  Peruvian  cotton  is  used  in  the  manufacture 
of  merino  goods,  being  mixed  in  varying  proportions  with  wool  fibre.  It  finds 
an  extensive  use  in  the  manufacture  of  mixed  woolen  underwear.  When  carded 
its  resemblance  to  wool  is  very  close  and  its  characteristics  are  quite  similar  to 
the  animal  fibre,  having  a  rough  woolly,  strong,  and  crinkly  staple.  So  that  when 
woven  in  fabrics  along  with  wool,  from  a  casual  examination  the  cotton  fibre 
is  not  apparent.  When  mixed  with  wool  it  reduces  the  tendency  of  the  fabric 
in  which  it  is  used  to  shrink;  it  also  gives  a  good  lustre  and  finish,  besides 
reducing  the  cost  of  manufacture.  For  these  reasons  it  is  largely  used  with  wool 
in  the  manufacture  of  underwear  and  hosiery. 


COTTON  223 

cotton  is  often  called  kidney  cotton,  being  characterized  by  the 
seeds  in  each  lobe  of  the  capsule  clinging  together  in  a  compact 
cluster.  These  seeds  are  black  and  without  a  persistent  fuzzy 
covering.  The  lint  shows  a  wide  variation  in  color  and  texture 
—white,  brown,  reddish,  rough  and  harsh,  or  smooth  and  soft. 
Most  of  it  has  a  shorter,  coarser,  and  more  wiry  fibre  than  that 
of  American  upland.  The  lint  of  some  varieties  is  much  like  wool 
in  appearance.  It  is  imported  chiefly  for  mixing  with  wool  or  for 
producing  special  effects.  Kidney  cotton  is  found  in  Central 
America  and  also  in  the  Philippines  and  other  tropical  islands 
of  the  Pacific,  but  it  is  not  cultivated  in  commercial  quantities 
outside  of  South  America.*  In  length  of  staple  it  varies  from 
ij  to  ITG  inches,  with  a  mean  of  i-J  inches;  its  mean  diameter 
is  about  0.00078  inch.  Most  of  the  fibres  are  only  partially 
twisted.  Smooth  Peruvian  has  a  soft,  smooth  feel,  but  the  staple 
is  not  so  strong  as  the  preceding.  The  length  is  about  the  same 
as  the  foregoing,  as  is  also  the  diameter.  Pernambuco  has  a 
slight  golden  color  and  feels  harsh  and  wiry.  It  is  a  variety  of 
Brazilian  cotton.  It  is  rather  regular  in  length  of  staple,  the 
mean  being  ij  inches.  The  diameter  averages  0.00079  inch. 
Under  the  microscope  the  twists  appear  regular  and  well  defined. 
Maranhams  is  a  Brazilian  cotton  very  similar  to  the  preceding  in 
microscopic  appearance  and  length  and  diameter  of  staple.  Gear  a 
is  also  a  Brazilian  cotton,  rather  inferior  to  the  others  by  reason 
of  its  considerable  variation  in  length  of  staple.  Maceo  is  a  similar 
variety,  but  somewhat  harsher.  West  Indian  cottons  nearly 
all  belong  to  the  peruvianum  species;  they  are  usually  long 
in  staple  and  harsh  and  wiry  in  feel,  and  only  of  moderate 
strength.  The  length  is  quite  uniform  and  averages  ij  inches. 
The  diameter  varies  considerably,  but  has  an  average  of  about 
0.00077  inch.  The  twist  is  short  and  very  uniform,  surpassing 
even  sea-island  in  this  respect. 

Gossypium  arboreum. — This  includes  the  majority  of  the 
Bengal  and  Chinese  cottons  of  commerce.  A  variety  of  Chinese 
cotton  known  as  Nankin  cotton,  is  classified  as  G.  religiosum; 

*  Yearbook,  U.  S.  Dept.  Agric.,  1903. 


224  THE  TEXTILE   FIBRES 

it  yields  a  naturally  colored  fibre,  being  rather  dark  yellowish 
brown.  It  grows  principally  in  China  and  Siam.  The  Dacca 
cotton  from  which  the  famous  muslins  were  made,  is  said  to  be 
derived  from  G.  neglectum,  a  variation  of  G.  arboreum.  This 
species  is  indigenous  to  India  where  it  was  estensively  grown 
as  a  field  crop.  The  boll  is  small  in  size  and  contains  ojte^  a 
small  number  of  seeds.  The  fibre  is  remarkable  for  its  'fineness 
and  silkiness,  though  it  has  a  rather  short  staple.  During 
the  past  century,  the  cultivation  and  quality  of  this  cotton 
has  seriously  declined,  though  it  is  still  grown  in  a  very  restricted 
area.  The  G.  arboreum  is  also  grown  extensively  in  Africa. 

4.  Grading  of  Cotton. — The  principal  factors  in  the  grading 
of  cotton  are  length  of  staple,  uniformity,  strength,  color, 
cleanliness,  and  flexibility.  The  first  may  be  determined  by 
the  gradual  reduction  of  a  tuft  of  cotton  by  the  hand  until 
individual  fibres  are  drawn  from  the  tuft,  so  that  their  length 
may  be  ascertained.  The  uniformity  of  staple  is  also  important, 
for  if  the  staple  is  uneven  the  cotton  is  of  less  value  than  if  it 
were  somewhat  shorter  but  more  even.  The  color  of  the  fibre 
must  also  be  considered,  because  this  is  of  importance  in  main- 
taining an  even  shade  of  yarn.  The  cleanliness  of  the  fibre 
affects  the  amount  of  waste  made  in  the  mill  and  hence  is  an 
item  of  great  importance.  The  flexibility  of  the  cotton  is 
best  ascertained  by  the  feel;  flexibility  does  not  necessarily 
imply  lack  of  strength,  but  rather  includes  it,  for  a  weak  fibre 
is  more  liable  to  be  brittle  than  flexible.  On  the  other  hand, 
a  fibre  may  also  be  strong  and  harsh  and  yet  not  flexible,  and 
hence  less  suitable  for  fine  spinning.  The  strongest  cottons 
are  used  for  warp  yarns  as  such  yarn  is  required  to  withstand 
considerable  strain  during  weaving,  a  feature  which  is  not 
required  to  such  an  extent  by  filling  yarns.  The  latter,  how- 
ever, require  a  soft  and  flexible  fibre.  The  classification  of 
American  mainland  cottons  is  generally  done  by  means  of 
seven  full  grades,  which  may  also  be  divided  into  half  and  quarter 
grades,  thus  giving  a  scope  of  7  full,  13  half,  or  25  quarter  grades, 
as  circumstances  demand.  The  full  grades  are:  Fair,  Middling 
Fair,  Good  Middling,  Middling,  Low  Middling,  Good  Ordinary, 


COTTON  225 

and  Ordinary.  The  half  grades  are  designated  by  the  prefix 
"  Strict;"  and  the  quarter  grades  by  the  prefixes  "  Barely," 
meaning  the  intermediate  quality  between  the  half  grade  and 
the  next  full  grade  above,  and  "  Fully  "  which  is  between  the 
half  grade  and  the  next  full  grade  below.  Sea-island  cottons 
are  graded  as  follows.  Extra  Fine,  Fine,  Medium  Fine,  Good 
Medium,  Medium,  Common,  and  Ordinary.  Egyptian  cottons 
as  a  rule,  are  quoted  under  four  or  five  grades:  Good,  Fully 
Good  Fair,  Good  Fair,  and  Fair.  Between  the  grades  Good 
and  Fully  Good  Fair,  there  is  often  an  intermediate  adopted, 
called  Extra  Fully  Good  Fair.  In  the  commercial  grading  of 
cotton  a  classification  is  adopted  with  reference  to  the  quality 
of  the  fibre.  The  usual  grades  are  as  follows: 

Fair  Good  middling 

Strict  middling  fair  Strict  middling 

Middling  fair  Middling 

Strict  good  middling  Strict  low  middling 

Strict  good  ordinary  Middling  tinged 

Good  ordinary  Strict  low  middling  tinged 

Strict  good  middling  tinged  Low  middling  tinged 

Good  middling  tinged  Middling  stained 

The  "  fair,"  "  middling  fair,"  "  middling,"  etc.,  are  known 
as  full  grades,  while  those  intermediate  are  half  grades.*     The 

*  The  above  list  of  eighteen  grades  are  those  deliverable  upon  contracts  of 
the  New  York  Cotton  Exchange  (April,  1908).  Prior  to  January  i,  1908,  nine 
other  intermediate  grades,  known  as  "quarter  grades,"  were  recognized,  but  these 
were  eliminated  on  that  date,  as  were  also  two  other  grades,  "  low  middling  stained  " 
and  "strict  good  ordinary  tinged."  On  April  i,  1908,  "strict  low  middling 
stained"  was  also  excluded  from  the  list  of  deliverable  grades  in  the  New  York 
market. 

The  grades  from  fair  to  good  ordinary  in  the  above  list  are  what  is  known  as 
white  cotton.  The  "tinged"  and  "stained"  grades  are  cotton  showing  dis- 
coloration. Tinged  cotton  is  cotton  that  is  only  moderately  discolored;  that 
which  is  deeply  discolored  is  known  as  stained  cotton.  The  grade  names  given 
in  the  above  list  are  used  in  nearly  all  Southern  markets.  The  terms  "tinged" 
and  "stained",  however,  are  used  in  the  South  in  a  general  way  to  indicate  cotton 
of  the  respective  grades  which  has  become  more  or  less  discolored,  rather  than 
to  indicate  a  distinct  style  of  cotton,  as  at  New  York.  The  range  of  grades 
deliverable  on  contract  in  New  Orleans  is  about  the  same  as  that  permitted  by 
the  New  York  contract.  The  New  Orleans  contract,  however,  contains  the 
important  provision  that  no  cotton  shall  be  deliverable  which  is  of  a  lower  market 
value  than  good  ordinary  cotton  of  fair  color.  The  New  Orleans  contract  thus 


226  THE  TEXTILE  FIBRES 

"  middling"  grade  is  the  one  universally  employed  as  a  basis 
for  all  cotton  trading,  and  the  price  of  cotton  is  fixed  on  this 
standard. 

excludes  considerable  cotton  which  until  recently  has  been  tenderable  on  contracts 
at  New  York.  Moreover,  the  New  Orleans  classification  is  generally  conceded 
to  be  more  rigid,  grade  for  grade,  than  that  of  New  York;  so  that  cotton  of  a  given 
grade  name  in  the  New  York  classification  might  not  necessarily  be  given  the  same 
grade  in  New  Orleans. 

In  the  trade,  the  grades  above  middling  are  usually  referred  to  as  the  "higher 
grades,"  and  those  below  as  the  "lower  grades." 

An  important  feature  of  future  business  in  cotton  is  that,  broadly  speaking, 
cotton  delivered  on  contract  consists  of  the  surplus  grades  or  remnants  of  the 
more  desirable  grades.  Even-running  cotton — that  is,  cotton  of  substantially 
one  grade —  can  ordinarily  be  sold  to  spinners  at  a  premium  above  the  price  of  a 
mixed  assortment  of  grades;  consequently  buyers  will  not  pay  as  much  for  a  mixed 
assortment  of  cotton  as  for  even-running  cotton.  The  spot  merchant,  therefore, 
endeavors  to  class  out  his  cotton  into  even-running  lots  and  to  dispose  of  it  in 
the  spot  market  instead  of  tendering  it  on  contract,  using  the  contract  market 
to  get  rid  of  surplus  grades  or  broken  lots,  known  in  the  trade  as  "overs."  For 
these  reasons  a  mixed  assortment  of  grades  is  often  delivered  on  a  single  contract. 


CHAPTER  XI 
THE  PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON 

i.  Physical  Structure. — Physically  the  individual  cotton 
fibre  consists  of  a  single  long  tubular  cell,  with  one  end  attached 
directly  to  the  surface  of  the  seed.  Its  length  is  about  1200  to 
1500  times  its  breadth.  The  outer  end  of  the  fibre  is  pointed 
and  closed;  the  end  originally  attached  to  the  seed  is  generally 
broken  off  irregularly.  While  growing  the  fibre  is  round  and 
cylindrical,  having  a  central  canal  running  through  it;  but, 
after  the  enclosing  pod  has  burst,  the  cells  collapse  and  form  a 
flat  ribbon-like  fibre,  which  shows  somewhat  thickened  edges 
under  the  microscope.  The  juices  in  the  inner  tube,  on  the 
ripening  of  the  fibre,  are  drawn  back  into  the  plant,  or  dry 
up  on  exposure  to  light  and  air,  and  in  so  doing  cause  the  fibre 
to  become  twisted  into  the  form  of  an  irregular  spiral  or  screw- 
like  band,  by  reason  of  the  unequal  collapse  and  contraction 
of  the  cell- wall.  The  number  of  twists  in  the  cotton  fibre  in 
the  raw  state  is  said  to  be  from  150  to  400  per  inch.  Bowman* 
gives  the  following  table  as  an  approximate  estimate  of  the  mean 
number  of  twists  per  inch  in  various  classes  of  cotton: 

Sea-island 300 

Egyptian 228 

Brazilian 210 

American  peeler 1^2 

Indian  (Surat) 150 

Fibres  that  have  not  ripened  differ  somewhat  in  these 
characteristics,  being  straight  and  having  the  inner  canal  more  or 
less  filled,  in  consequence  of  which  they  do  not  spin  well  and 
are  difficult  to  dye,  showing  up  as  white  specks  in  the  finished 
goods;  this  is  known  as  dead  cotton.  The  presence  of  "  dead  " 
or  unripe  cotton  is  very  objectionable,  as  the  fibre  is  weak 
and  brittle,  and  consequently  reduces  the  strength  and  durability 

*  The  Structure  of  the  Cotton  Fibre,  p.  118. 

227 


228  THE  TEXTILE  FIBRES 

of  the  yarn  into  which  it  may  go.  There  is  a  considerable  amount 
of  unripe  or  partly  ripened  bolls  always  to  be  found  in  cotton- 
fields,  and  the  fibres  from  these  consist  almost  exclusively  of 
"  dead  cotton."  The  proper  utilization  of  such  cotton  is  a 
serious  question,  for  the  fibre  is  too  weak  to  be  used  for  spinning, 
and  the  cost  of  gathering  and  ginning  makes  the  fibre  too 
expensive  for  most  other  purposes,  such  as  for  absorbent  cotton, 
cotton  batting,  or  material  for  guncotton.  According  to  H. 
Kuhn,*  a  greater  proportion  of  dead  fibres  occurs  in  the  coarser 
varieties  of  cotton  than  in  the  finer,  a^^Hnis  is  accounted 
for  by  the  fact  that  such  fibres  draw  up  tirore  juice  from  the 
seed,  which  thus  becomes  impoverished  before  the  maturity 
of  all  the  adhering  fibres.  Dead  cotton  is  far  more  common  in 
Indian  cottons  than  in  sea-island  or  Egyptian.  Hallerf  states, 
that  unripe  cotton  fibres  differ  from  the  matured  fibres  in  their 
chemical  behavior.  A  potassium  iodide  solution  of  iodin 
gives  a  dark  yellowish  brown  color  with  the  ripe  fibres  while 
the  dead  fibres  remain  a  light  yellow.  On  treatment  with  a 
zinc  chloride  solution  of  iodin  dead  cotton  gives  a  blue  colora- 
tion more  rapidly  than  the  normal  fibre.  The  dead  fibres 
also  show  a  different  reactivity  towards  many  dyestuffs.J 

*  Die  Baumwolle. 

t  Chem.  Zeit.,  1908,  p.  838. 

J  Haller  (Chem.  Zeit.,  1908,  p.  838)  gives  the  following  description  of  the  prop- 
erties of  unripe  cotton.  Under  the  microscope  the  lumen  is  seen  to  contain  a 
considerable  quantity  of  matter,  and  the  fibres  do  not  appear  so  twisted  as  the 
ripe  fibres.  When  treated  with  an  ammoniacal  solution  of  copper  oxide,  the 
fibres  of  dead  cotton  swell  up  but  do  not  dissolve.  When  a  mixture  of  ripe  and 
unripe  fibres  is  treated  with  a  solution  of  chlor-iodide  of  zinc,  the  unripe  fibres 
very  quickly  develop  a  blue  color,  which  appears  much  more  slowly  with  the 
ripe  fibres.  A  solution  of  iodin  in  potassium  iodide  colors  the  ripe  fibres  a  dark 
yellowish  brown,  whereas  the  unripe  fibres  acquire  only  a  light  yellow  color. 
When  treated  with  an  18  per  cent  solution  of  caustic  soda,  the  unripe  fibre  retains 
what  twist  it  has,  and  only  becomes  lighter  and  more  transparent.  The  ripe 
and  unripe  fibres  also  exhibit  marked  differences  towards  polarized  light.  If  a 
mixture  of  the  two  classes  of  fibres  is  boiled  in  caustic  soda  solution  (2°  Be.), 
and  then  soured,  washed,  and  dyed  with  indigo,  the  ripe  fibres  take  up  the  dyestuff 
readily,  but  the  unripe  fibres  are  dyed  to  only  a  very  limited  extent.  The  reverse, 
however,  is  the  case  when  dyeing  with  the  substantive  dyes,  the  unripe  fibres 
acquiring  a  deeper  color.  When  dyed  with  basic  colors  on  a  tannin-antimony 
mordant,  the  unripe  fibre  is  only  dyed  on  the  exterior. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     229 


The  presence  of  an  inner  canal  in  the  cotton  fibre  no  doubt 
adds  to  its  absorptive  power  for  liquids,  and  its  capillary  action 
allows  cotton  to  retain  salts,  dyestuffs,  etc.,  with  considerable 
power;  but  too  much  importance  in  this  respect  must  not  be 
attributed  to  the  canal,  for  when  cotton  is  mercerized  the 
canal  is  almost  entirely  obliterated  by  the  walls  being  squeezed 
together  (see  Fig.  60),  and  yet  mercerized  cotton  is  much  more 
absorptive  of  dyes,  etc.,  than  ordinary  cotton.  The  capillarity 
of  the  cotton  fibre  is  no  doubt  principally  due  to  the  existence 
of  minute  pores  which  run  from  the  surface  inward.  The 
crystallization  of  salts  in  these  pores  and  in  the  central  canal 
may  lead  to  the  rupturing  of  the  fibre,  as,  for  instance,  when 
filter-paper  is  made  by  disintegrating  cotton  fibres  by  saturating 
with  water  and  then  freezing. 

2.  Dimensions  of  Cotton  Fibres. — The  following  table  of 
the  length  and  diameter  of  different  varieties  of  cotton  fibres 
has  been  collated  as  a  mean  of  several  observers: 


Name  of  Cotton. 

Length 
in  mm. 

Diameter 
in  ft. 

Name  of  Cotton. 

Length 
in  mm. 

Diameter 
in  M. 

Sea-island  

41  .Q 

9.61; 

West  Indian  

32  .  3 

19  6 

Edisto 

46  6 

American      

20  o 

Wodomalam  

39.  o 

Orleans  

27.0 

19   2 

John  Isle  

39-  1 

Upland  

29    < 

10  4 

Florida      ....... 

AC     7 

16.  18 

Texas  

24   3 

16  6 

Fitschi 

48  7 

16  7 

Mobile 

2  C    o 

IO    4 

Tahiti  

42  .9 

16.3 

Georgia  

2C    4 

IO    3 

Peruvian 

38  9 

1C  .  2 

Mississippi    .    .  . 

24    2 

13    4 

Esytotian 

32    I 

16  7 

Louisiana 

2  C    O 

Gallini 

27    2 

17    I 

Tennessee 

2C    i 

I  C    O 

Brown         .    .  . 

34   4 

18.7 

African   

27    6 

2O   8 

White 

31     8 

10    *» 

Indian 

IO    3 

Smyrna  

28.5 

22.8 

Hingunghat  

28.3 

2O   O 

Brazilian 

18.8 

Dhollerah   

28.2 

21    <? 

Maranham 

28  8 

2O  4 

Broach         . 

2O   O 

21    8 

Pernambuco  

31?  •  2 

2O.  O 

Tinnevelly  

23  .O 

21  .0 

Surinam  

3O    2 

Dharwar       ..... 

23    6 

21    O 

Paraiba  
Ceara  

29.7 
28.1 

2O.  O 

Oomrawuttee  .... 
Comptah  

24.1 
23.8 

21-5 
21  .  S 

Maceo.  . 

29    3 

Madras  

21.8 

21.8 

Peruvian  rough 

20.  0 

21  «; 

Scinde           .... 

2O  4 

21  .  3 

Smooth  

3O.O 

21  .  < 

25.7 

23.7 

Agerian  

37.  c 

21  .4 

24.1 

230 


THE  TEXTILE   FIBRES 


The  cotton  fibre  is  rather  even  in  its  diameter  for  the  greater 
part  of  its  length,  though  it  gradually  tapers  to  a  point  at  its  out- 
growing end.  The  different  varieties  of  cotton  show  considerable 
variation,  both  in  length  and  diameter  of  fibre;  in  sea-island 
cotton  the  length  is  nearly  2  inches,  while  in  Indian  varieties  it 
is  often  less  than  i  inch.*  The  diameter  varies  from  0.00046 
to  o.ooi  inch;  the  longest  fibres  having  the  least  diameter.! 


&  ^tt:B 

/n  ®  cL^ 

<^>(fe 

;&a  >-? 


FIG.  60. — Cross-sections  of  Mercerized  Cotton  Fibres,  showing  the  Appearance 

of  the  Inner  Canal. 

*  Bulletin  No.  33  (U.  S.  Dept.  Agric.)  gives  the  following  table  compiled 
from  numerous  measurements  taken  during  a  period  of  years,  showing  the  maxi- 
mum, minimum,  and  average  length  of  fibre  for  some  of  the  most  important 
varieties  of  cotton,  as  well  as  the  average  diameter  of  the  same: 


Variety. 

Length  in  Inches. 

Diameter, 
Inches. 

Maximum 

Minimum. 

Average. 

Sea-island  
New  Orleans          

1.  80 
1.16 

I  .  12 
I.  06 
1-52 
I-3I 

I  .02 
I  .  21 
1.65 

1.41 

0.88 
0.87 
0.81 
1.30 
1.03 

0.97 
0-95 
1-36 

I.6l 
1  .02 
I  .OO 

0-93 
1.41 
1.17 

0.89 
1.  08 
1-5° 

o  .  000640 

0.000775 
0.000763 
0.000763 
0.000655 
0.000790 

o  .  000844 
0.000825 

0.000730 

Texas 

Upland..  
Egvptian 

Brazilian  

Indian  varieties: 
Native  ....         

American  seed 

Sea-island  seed  

From  these  measurements  it  will  be  observed  that,  as  a  rule,  the  longer  the 
fibre  the  less  is  its  diameter.  The  extreme  variations  in  the  above  measurements 
of  length  is  from  0.25  to  0.30  inch.  In  proportion  to  the  size  of  the  fibre,  the 
variation  in  diameter  is  much  greater  than  that  for  the  length. 

t  Deschamps  (Le  Colon,  p.  165)  classifies  commercial  cottons  into: 
(a)  Fine  cotton  with  fibres  up  to  20  \L  diameter. 
(V)  Ordinary  cotton  with  fibres  from  20  ^  to  23  jx. 
(c)   Coarse  cotton  with  fibres  of  23  u.  and  over. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     231 


Evan  Leigh  *  gives  the  following  summary  of  the  length 
and  diameter  of  cotton  fibres: 


Place  of  Growth. 

Kind  of  Cotton. 

Length  in  Inches. 

Diameter  in  Inches. 

Min. 

Max. 

Mean. 

Min. 

Max. 

Mean. 

United  States  .  . 
Sea-islands.  .  .  . 
South  America  . 
Egypt  

New  Orleans  .  .  . 
Long  stapled.  .  . 
Brazilian  

0.88 
1.41 
1.03 
1.30 
0.77 
o-95 
1.36 

1.16 
1.  80 
I-3I 
1-52 
•  1  .02 

I  .  21 
1-65 

1.02 
I.6l 

I-I7 
I.4I 
0.89 
1.  08 
1-50 

.  000580 
.000460 
.000620 
•  000590 
.000649 
.000654 
.000596 

.000970 
.000820 
.  000960 
.000720 
.000040 
.000996 
.  000864 

.000775 
.000640 
.000790 
.000655 
.000844 
.000825 
.000730 

Egyptian  

India  .  .        .  .  \ 

Native 

American  seed.  . 
Sea-island  seed. 

1 

Hannan  gives  the  following  varieties  and  qualities  of  cotton 
to  be  met  with  in  commerce: 


Types. 

Variety. 

L'gth, 
Ins. 

Diam- 
eter, 
Ins. 

Counts. 

Use. 

Properties. 

•4 

Sea-island.  . 

Edisto  

Florida  
Fiji  . 

2.20 
1-85 

I  7C 

.00063 

.00063 
00063 

300-400 

.150-300 
100—250 

Warp 
or  weft 

do. 
do 

Long,  fine  silky, 
and     of     uniform 
diameter 
Shorter,  but  similar 
to  above 
Less     uniform     i  n 

Tahiti  

i  80 

00063 

100-250 

do. 

length,    but   silky 
and  cohesive 
Good,     fine      and 

Egyptian.   . 

Brown  
Gallini  
Menouffieh.  .  . 
Mitafifi. 

1-50 
i.  60 

1-5° 

I  2S 

.00070 
.00066 
.00066 
00066 

1  2O-down 
25o-down 
2oo-down 

IOO 

do. 
Warp 
Weft 
Warp 

glossy  staple 
Long,  strong,  high- 
ly endochromatic 
High-class  staple  of 
good  strenght 
Of  good  staple  and 
lustre 
Fairly  good  staple 

White  

I  .OO 

.00078 

70 

or  weft 
do. 

Pearly  white,  good 

Peruvian.  .  . 

Rough  
Smooth 

1-25 
I  OO 

.00078 
00078 

50-70 

CO—  7O 

Warp 
Weft 

long  staple 
Strong,  wooly,  and 
harsh  staple 
Less    woolly     and 

Red 

I  2^ 

00078 

An—eo 

Warp 

softer  staple 
Color    weaker    and 

harsher     than 
brown  Egyptian 

*  Science  of  Modern  Cotton  Spinning. 


232 


THE   TEXTILE  FIBRES 


Types. 

Variety. 

L'gth, 
Ins. 

Diam- 
eter, 
Ins. 

Counts. 

Use.' 

Properties. 

Brazillian.  .  . 

Pernambuco  . 
Maranham.  .  . 
Ceara 

1-5° 
I-I5 
I  I  ^ 

.00079 
.00079 
OOO7O 

50-70 
50-60 
60 

Warp 
do. 
Weft 

Strong  and  wiry 
Harsh  and  wiry 
Good    white    and 

Paraiba  

I  2O 

OOO7O 

^O-6o 

Warp 

cohesive  staple 
Fairly  strong,  harsh, 

Rio  Grande  .  . 
Maceio  
Santos  

Bahia 

i.  IS 

I  .  20 
1.30 

.00079 
.00084 
.00084 

40-50 
40-60 
50-60 

4.O—^O 

or  weft 
Weft 

Warp 
or  weft 
Weft 

W^arp 

of  good  color 
Soft,    white,    and 
harsh  staple 
Soft,   pliable,   and 
good  for  hosiery 
Exotic  from  Ameri- 
can seed,  white 
and  silky  staple 
Fairly  strong    but 

American  .  . 

Orleans 

I  j 

OOO77 

or  weft 
do 

harsh  and  wiry 
Medium  length 

Texas  

I  O$ 

OOO7/ 

32—  4O 

do. 

pearly^  white 
Similar    to    above, 

Allanseed.  .  .  . 
Mobile  

1  .  20 
1  .00 

.00077 
00076 

5O-60 
4O—^O 

Warp 
Warp 

rather  harsher  and 
more  glossy 
Good,  white,  long; 
blends  with  brown 
Egyptian 
Even-running     sta- 

Norfolks   
St.  Louis  .... 
Roanokes.  .  .  . 
Boweds.  ..... 

1  .00 
0.90 
0.90 

» 

.00076 
.OOO76 
.OOO76 

40-50 
3<^32 
30-34 
16 

or  weft 
Weft 
Warp 
do. 
Weft 

ple,  soft  and  cohe- 
sive 
Used    for    Oldham 
counts  of  5o's 
Staple    irregular, 
glossy,  but  short 
A  white  and  strong 
staple 
Similar  to  uplands 

Benders 

I  IO 

OOO77 

60 

Warp 

Strong     creamy   or 

Memphis  .... 
Peelers  

1  .00 

I  •  2$ 

.00077 
.OOO77 

40-50 
60-80 

do. 
Weft 

white,  for  Turkey- 
red  dyes 
Bluish  white,  for  ex- 
tra hard  twists 
Long,   silky,    fine 

Uplands  
Alabama  .... 

I.  00 
0.90 

.00077 
.00077 

36-40 
26-30 

do. 

Warp 
or  weft 

staple;       adapted 
for  velvets,  etc. 
Glossy  when  clean, 
apt    to    be    dull, 
sandy,  and  leafy 
Short  staple,  of  less 
strength,    varying 
color 

PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     233 


Types. 

Variety. 

L'gth, 
Ins. 

Diam- 
eter, 
Ins. 

Counts. 

Use. 

Properties. 

American  .  . 

Linters  

8-Ip 

Weft 

Short  -  stapled    gin 

waste 

Tennessee.  .  .  . 

0.90 

.00077 

28 

Warp 

Of    varying    length 

or  weft 

and  color 

Greek  

Smyrna 

I  .  25 

36—  40 

Warp 

Harsh    and    strong 

O           T^ 

adapted  for  double 

yarns 

African  .... 

Lagos  

0.80 

20-26 

Weft 

Dull  and  oil-stained, 

irregular  in  length 

and  strength 

West  Indian 

Carthagena  .  . 

1.50 



26 

Warp 

From  exotic  seeds; 

fairly  strong 

La  Guayran.  . 

I  .  2O 

....'.. 

40 

Warp 

Irregular  and  short, 

or  weft 

but  silky  staple 

China  ..... 

China  

I  .OO 

3° 

Weft 

Harsh,    short,    and 

white 

Australian.  . 

Queensland  .  . 

J7-5 

.00066 

I  20-200 

Warp 

Long,  white,  silky, 

or  weft 

fine  diameter 

East  Indian. 

Oomrawuttee. 

i  .00 

.00083 

26-32 

.  Warp 

Short,    strong,   and 

white 

Hingunghat  . 

i  .00 

.00083 

28-36 

Weft 

Best   white   Indian 

staple 

Comptah  .... 

I  .CX 

Warp 

Generally  dull  and 

or  weft 

charged  with  leaf 

Broach  

0.90 

28-36 

Weft 

Like     Hingunghat, 

gives  good   white 

weft 

Dharwar  

I  .00 

28 

Warp 

Exotic  from  Ameri- 

can seeds 

Assam  

0.50 

15-20 

Warp 

White,    but    harsh, 

to  blend  with  other 

cottons 

Bengals  

0.80 

20-30 

Warp 

Dull  and  generally 

or  weft 

charged  with  leaf 

. 

Bilatu  

0.50 

...... 

10-20 

do. 

Weak,  brittle,  and 

coarse 

Dhollerah  

0.70 

15-20 

do. 

Strong,  dull,  and  co- 

hesive 

Surat  

0.60 

10—  is 

do. 

Dull  and  leafy,of  ten 

J 

stained 

Scinde  

o.  so 

to  10, 

do. 

Very    strong,    dull, 

««  -  ^v 

short,    and    poor 

staple 

Tinnevelly  .  .  . 

0.80 



24-30 

do. 

Lustrous  white,soft, 

and    adapted    for 

hosiery 

Bhownuggar  . 

1  .00 

28-30 

Warp 

White  when  clean; 

often    leafy    and 

• 

dirty 

234 


THE  TEXTILE  FIBRES 


Types. 

Variety. 

L'gth, 
Ins. 

Diam- 
eter, 
Ins. 

Counts. 

Use. 

Properties. 

East  Indian. 

Cocoanada 

O   7O 

10-14 

Brown 

Brown     and     dull  * 

w  .   i  w 

weft 

used     as     quasi- 

Egyptian 

Bourbon  

1  .00 

30 

Weft 

Exotic;  of  good  sta- 

ple; scarce 

Khandeish  .  .  . 

0.80 

.00083 

20-26 

Warp 

Similar  in  class  to 

or  weft 

Bengal 

Madras     o  r 

o.  70 

1^-20 

do. 

Used  for  low  yarns 

Westerns. 

o 

in  coarse  towelling, 

etc. 

Rangoon. 

o.  60 

to  10 

Warp 

Weak,    dull,    often 

or  weft 

stained  and  leafy 

Kurrachee  .  .  . 

0.90 

28 

do. 

Fairly  strong,  dull, 

and  leafy 

Italian  

Calabria  

0.90 

26-28 

do. 

Fairly  strong,  irreg- 

ular and  dull,leafy 

Turkey  

Levant  

1-25 

.00077 

36-40 

Warp 

Harsh,  strong,  and 

white 

Monie  *  gives  the  following  tables  descriptive  of  the  principal 
commercial  varieties  of  cotton.  As  the  descriptions  given  in 
these  tables  vary,  in  some  respects,  quite  considerably  from  the 
preceding  tables  of  Hannan,  it  is  probably  best  that  both  should 
be  given  for  comparison. 

Monie  remarks  in  connection  with  this  table  that  it  will 
be  observed  that  the  Fiji  and  Tahiti  sea-island  cottons  are  the 
most  irregular  in  the  length  of  their  fibres,  the  extreme  variation 
in  both  'being  half  an  inch.  As  long  and  short  cotton  never 
incorporate  well  together  nor  adapt  themselves  to  the  produc- 
tion of  a  yarn  regular  in  appearance  and  strength,  it  is  easy 
to  understand  that  they  are  relatively  wasteful  cottons  to  work. 
In  any  spinning  mill  where  they  are  used,  it  will  be  found  that 
the  quantity  of  "  fly,"  "  combings,"  and  "  flat  waste  ".made  at 
the  various  machines  is  very  great,  and  the  reason  of  this  is  that 
in  any  cotton  where  the  fibres  are  of  different  lengths,  the  long 
and  strong  will  have  a  tendency  to  throw  out  the  short  and  weak. 
The  cotton  which  presents  the  greatest  regularity  is  the  Orleans. 
In  comparing  the  diameters  of  various  cottons  with  their  lengths, 
it  will  be  found  that  the  longest  cottons  are  usually  the  finest. 

*  The  Cotton  Fibre. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     235 


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THE  TEXTILE  FIBRES 


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Finest  of  American  white  cottons; 
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PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     237 


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238 


THE  TEXTILE   FIBRES 


Hohnel  gives  the  following  table  for  the  thickness  of  dif- 
ferent varieties  of  cotton: 


North  American: 

Sea-island 

Louisiana  and  Alabama 

Florida 

Upland  and  Tennessee 


Thickness  in 
...       14 

17 

. ... .       18 

19 


Southern  and  Central  American 15-21 

Average 19 

East  Indian: 

Dollerah  and  Bengal 20 

Madras 28 

Chinese: 

Nankin 25-40 

Egyptian: 

Makko 15 

Levantine 24 

European: 

Spanish 17 

Italian 19 

According  to  Wiesner,  the  thickest  part  of  the  cotton  fibre  is 
not  directly  at  the  base,  but  more  or  less  towards  the  middle. 
He  gives  the  following  measurements  of  thickness  at  different 
parts  of  the  fibre: 


Position. 

'G.  arbor  eum, 
25  mm.  long. 

G.  acuminatum, 
28  mm.  long. 

G.  herbaceum, 
25  mm.  long. 

M 

M 

M 

Point 

0 

O 

O 

I 

8.4 

4-2 

4-2 

2 

21 

21.6 

5-8 

3 

29 

16.8 

IO.O 

4 

25 

29.4 

16.8 

5 

29 

17.0 

21  .O 

6 

25 

21  .  I 

16.9 

7 

21 

21.  I 

21.0 

Base 

17 

21  .O 

16.8 

Mean 

19-5 

16.9 

12.5 

The  length  of  the  cotton  fibres  attached  to  a  single  seed  is  by 
no  means  constant.     The  longest  fibres  usually  appear  at  the 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON    239 

crown  of  the  seed,  while  the  shortest  occur  at  the  base.  There 
is  also  frequently  an  undergrowth  of  very  short  fuzzy  fibres. 
In  ginning  the  purpose  is  not  to  remove  the  very  short  fibres, 
but  at  best,  more  or  less  of  them  appear  with  the  ginned  cot- 
ton. These  short  fibres  are  termed  "  neps,"  and  their  presence 
in  any  considerable  amount  materially  affects  the  commercial 
value  of  the  cotton.  This  short  undergrowth  of  neps  appears 
to  be  made  up  of  incompletely  developed  or  immature  fibres, 
though  neps  may  also  arise  through  excessive  breaking  of  fibres 
by  imperfect  manipulation  in  the  carding  and  spinning  processes. 
Bowman  *  gives  the  following  table  showing  the  extreme 
variation  in  the  length  and  diameter  of  different  kinds  of  cotton : 


Cotton. 

Variation  in 
Length. 

Variation  in 
Diameter. 

American  (Orleans)  
Sea-island  
Brazilian 

6.28  in. 

0-39" 
o  28  " 

0.000390  in. 
0.000360  " 
o  00034.0  '  ' 

Effvotian 

0    22  " 

o  000130  '  ' 

Indian  (Surat)  

o  25  " 

O    OOO3QI   " 

According  to  the  measurements  of  Wiesner,  the  average  width 
(diameter  of  the  broadside)  of  the  various  kinds  of  cotton  are 
as  follows: 

Gossypium  herbaceum 18 . 9  [i 

barbadense 25.2^ 

con glomer alum 25 . 5  (A 

acuminatum 29 . 4  ^ 

arboreum 29 . 9  (j. 

religiosum 33  3  ^ 

flamdum 37  •  8  [A 

Bowman  calls  attention  to  the  fact  that  Egyptian  cotton 
is  the  most  regular  in  both  length  and  diameter;  while  sea- 
island  cotton,  though  possessing  the  greatest  length  and  fineness 
of  staple,  also  exhibits  the  greatest  variation.  It  is  also 
noticeable  that  the  variation  in  the  diameter  is  proportionately 
very  much  larger  than  the  variation  in  the  length.  Bowman 


*  Structure  of  the  Cotton  Fibre. 


240 


THE  TEXTILE    FIBRES 


also  gives  an  interesting  comparison  of  the  size  of  the  individual 
cotton  fibre  with  objects  of  common  experience.  If  a  single 
fibre  of  American  cotton  were  magnified .  until  it  becomes  one 


' 

i 

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inch  in  diameter,  it  would  be  a  little  over  100  feet  long,  while 
a  sea-island  fibre  of  the  same  diameter  would  be  about  130  feet. 
It  requires  from  14,000  to  20,000  individual  fibres  of  American 
cotton  to  weigh  i  grain,  hence  there  are  about  140.000,000  in 
each  pound,  and  each  fibre  weighs  on  an  average  only  about 


PHYSICAL  STRUCTURE  AND   PROPERTIES   OF  COTTON     241 

0.00006  grain.  If  the  separate  fibres  contained  in  one  pound 
were  placed  end  to  end  in  a  straight  line,  they  would  reach 
2 200  miles.* 

Hohnel  gives  the  following  table  of  the  different  varieties 
of  cotton  arranged  according  to  their  length  of  staple : 

Gossyplum  barbadense         (Sea-island) 4.05  cm. 

(Brazilian) .  . 4.00  " 

(Egyptian) 3.89  " 

' '          vitifolium.          (Pernambuco) 3 . 59  " 

conglomeratum  (Martinique) 3-51  " 

acuminatum      (Indian) 2 . 84  ' ' 

' '          arboreum  (Indian) 2 . 50  " 

1 '          herbaceum         (Macedonian) .  . 1.82  ' ' 

(Bengal) 1.03  " 

3.  Anatomical  Structure. — From  its  behavior  with  a  solu- 
tion of  ammoniacal  copper  oxide,  the  cotton  fibre  appears  to 
consist  of  four  distinct  parts  structurally.  When  treated  with 
this  solution  and  examined  under  the  microscope,  the  fibre  is 
seen  to  swell,  but  not  uniformly;  it  seems  that  at  regular  intervals 
there  are  annular  sections  which  do  not  swell.  The  result 
is  that  the  fibre  assumes  the  form  of  a  distended  tube  tied  at 
intervals  somewhat  after  the  manner  of  a  string  of  sausages. 
Hohnel  considers  these  ligatures  as  merely  parts  of  the  cuticle; 
he  explains  their  formation  by  the  fibre  swelling  so  considerably 
as  to  rupture  the  undisturbed  cuticle,  which  in  places  adheres 
to  the  fibre  in  the  form  of  irregular  shreds  which  are  visible 
only  with  difficulty.  In  other  places  where  the  rupture  occurs 

*  Burkett  (Cotton,  p.  328)  gives  the  following  data  concerning  the  manufac- 
tured value  of  one  pound  of  raw  cotton  worth  10  cents: 

i  \  yards  of  denim  worth  18  cents. 

4  yards  sheeting  worth  20  cents. 

4  yards  bleached  muslin  worth  32  cents. 

7  yards  calico  worth  35  cents. 

6  yards  gingham  worth  45  cents. 
10  yards  shirtwaists  worth  $1.50. 
10  yards  lawn  worth  $2.50. 
25  handkerchiefs  worth  $2.50. 
56  spools  No.  40  sewing  thread  worth  $2.80. 

These  figures,  of  course,  are  only  approximate  averages. 


242  THE  TEXTILE  FIBRES 

obliquely  to  the  length  of  the  fibre,  the  cuticle  becomes  drawn 
together  in  annular  bands  surrounding  the  fibre,  while  between 
these  rings  the  much-distended  cellulose  protrudes  in  the  form 
of  globules.  The  inner  membrane  or  canal  which  persists 
after  the  rest  of  the  fibre  has  dissolved  is  an  exceedingly  thin 
tissue  of  dried  protoplasm  which  was  contained  in  the  living 
fibre.  On  bleached  cotton  the  cuticle  may  be  almost  entirely 
lacking,  and  hence  such  fibres  will  not  exhibit  the  character- 
istic appearance  above  mentioned.  When  the  fibre  has 
become  much  swollen  by  the  action  of  the  reagent  it  soon 
begins  to  dissolve,  whereupon  the  walls  of  the  central  canal 
are  seen  quite  prominently;  the  dissolving  action  proceeds 
rapidly,  but  apparently  there  is  a  thin  cuticular  tissue  surround- 
ing the  fibre  which  resists  the  action  of  the  solvent  for  a  much 
longer  time  than  the  inner  portion.  The  walls  of  the  central 
canal  also  resist  the  action  of  the  liquid  to  even  a  greater  extent 
than  the  external  tissue;  the  annular  contracted  ligatures  in 
the  fibre  also  persist  after  the  rest  of  the  fibre  has  dissolved. 
Thus  we  have  four  structural  parts  made  evident  (see  Fig.  64) : 

(a)  The  main  cell-wall,  probably  composed  of  pure  cellulose, 
and  rapidly  and  completely  soluble  in  the  reagent. 

(b)  An  external  cuticle,  probably  of  modified  cellulose,  and 
more  resistant  to  the  action  of  the  reagent. 

(c)  The  wall  of  the  central  canal,  which  resists  the  solvent 
power  of  the  reagent  even  more  than  the  cuticle. 

(d)  The  annular  ligatures  surrounding  the  fibre  at  intervals, 
which  persist  even  after  the  canal- walls  have  dissolved. 

O'Neill  (in  1863)  first  pointed  out  this  complex  structure  of 
the  cotton  fibre.  He  says:  "  I  believe  that  in  cotton-hairs  I 
could  discern  four  different  parts.  First,  the  outside  membrane, 
which  did  not  dissolve  in  the  copper  solution.  Second,  the  real 
cellulose  beneath,  which  dissolved,  first  swelling  out  enormously 
and  dilating  the  outside  membrane.  Thirdly,  spiral  fibres, 
apparently  situated  in  or  close  to  the  outside  membrane,  not 
readily  soluble  in  the  copper  liquid.  These  were  not  so  elastic 
as  the  outside  membrane  and  acted  as  strictures  upon  it,  pro- 
ducing bead-like  swellings  of  a  most  interesting  appearance;  and 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     243 

fourthly,  an  insoluble  matter,  occupying  the  core  of  the  cotton- 
hair,  and  which  resembled  very  much  the  shrivelled  integument 
in  the  interior  of  quills  prepared  for  making  pens."  He  also 
notes  that  the  insoluble  outside  membrane  was  not  evident  on 
bleached  cotton,  hence  concluding  that  either  it  had  been 
dissolved  away,  or  some  protecting  resinous  varnish  had  been 
removed,  and  then  it  became  soluble.  He  also  obtained  the 


FIG.  62. — Cotton  Fibre  Swollen  with  Schweitzer's  Reagent.     (X  600.)     Showing 
spirally  developed  lamella  in  fibre  walls.     (Micrograph  by  author.) 

!  "•  T'}  1 

same  general  results  by  treatment  with  sulphuric  acid  and 
chloride  of  zinc  in  place  of  the  ammoniacal  copper  oxide  solution. 
According  to  Butterworth,  who  observed  the  cotton  fibre 
treated  with  the  ammoniacal  copper  oxide  solution  under  a 
magnification  of  1600  diameters,  there  are  spiral  threads 
apparently  crossing  and  tightly  bound  round  the  fibre  at  irregular 
distances,  also  spiral  threads  passing  from  one  stricture  to  another; 
the  core  of  the  fibre  has  a  spiral  form,  and  in  cross-section  shows 
the  presence  of  concentric  rings. 


244 


THE  TEXTILE  FIBRES 


There  appears  to  be  some  difference  in  the  action  of  ammo- 
niacal  copper  oxide  solution  on  fibres  of  different  physiological 
structure.  Immature  or  unripe  fibres  dissolve  readily  without 
exhibiting  any  structural  differences.  The  tubular-shaped 
fibres  swell  out  as  a  whole  and  finally  dissolve  without  showing 
any  structural  modifications,  except  that  in  many  cases  an 
inner  core  is  left. 


FIG.  63. — Portion  of  Fig.  62  more  Highly  Magnified.     (Xi5oo.)     The  structure 
of  the  cotton  cellulose  is  here  plainly  visible.     (Micrograph  by  author.) 

Examination  with  the  highest  microscopic  powers  has  not 
shown  any  cellular  structure  pertaining  to  the  cellulosic  con- 
tents of  the  cotton  fibre;*  it  is  apparently  composed  of  fine 

*  The  spiral  fibrillae  occurring  in  the  cell-wall  of  the  cotton  fibre  can  be  readily 
observed  under  the  microscope  with  even  moderately  high  magnification  in  the 
case  of  cotton  rag  pulp  for  paper  manufacture.  The  cotton  fibres  under  these 
circumstances  have  been  so  broken  up  and  mechanically  bruised  and  partially 
disintegrated  that  the  individual  fibrillae  are  often  well  separated.  Kuhn  (Die 
Baumwolle)  concurs  with  the  author  in  the  opinion  that  the  cotton  fibre  is  made 
up  of  spirally  laid  fibrillae,  and  he  attributes  the  absorptive  power  of  cotton 
towards  solutions  to  the  permeable  spaces  occurring  between  these  nbrillas. 
Bowman  (Structure  of  Cotton  Fibre,  p.  105)  also  calls  attention  to  this  structure. 
This  structure  of  the  cell-wall  of  the  cotton  fibre  is  in  disagreement  with  the 
statement  of  De  Mosenthal  (Jour.  Soc.  Chem.  Ind.,  1904,  p.  292)  who  claims 


PHYSICAL   STRUCTURE  AND  PROPERTIES  OF  COTTON     245 

layers  of  spirally   laid  fibrillae    superimposed    one    upon  the 
other.* 

4.  Microscopy  of  Cotton  Fibre. — The  microscopical  char- 
acteristics of  the  cotton  fibre  are  so  pronounced  as  to  differen- 
tiate it  readily  from  all  others.  As  previously  noted,  it  presents 
the  appearance  of  a  flat,  ribbon-like  band,  more  or  less  twisted 


FIG.  64. — Appearance  of  Cotton  Fibre  on  Treatment  with  Schweitzer's  Reagent. 

(After  Witt.) 

a,  transverse  ligatures  of  disrupted  cuticle;    b,  irregular  shreds  of  cuticle  torn 
apart;  c,  swollen  mass  of  cellulose;  d,  walls  of  internal  canal. 

on  its  longitudinal  axis  (see  Fig.  65).  The  edges  of  the  fibre 
are  somewhat  thickened,  and  usually  present  irregular  corruga- 

that  the  cellulose  of  cotton  consists  of  minute  spherical  granules  about  i  (x  in 
diameter.  All  the  best  authorities  on  the  microscopy  of  cotton  are  opposed  to 
this  view  of  its  structure. 

*  According  to  Dreaper  (Chemistry  and  Physics  of  Dyeing,  p.  12)  the  outer 
sheath  of  the  cotton  fibre  is  considered  to  be  pure  cellulose,  while  the  inner  layers 
are  made  up  of  secondary  cellular  deposits;  or  are  formed  by  a  gradual  thickening 
of  the  outer  layer. 


246 


THE  TEXTILE  FIBRES 


FIG.  65. — Cotton  Fibres.     (Xsoo.)     Longitudinal  Views. 


FIG.   66.— Cross-sections  Cotton  Fibres.     (Xsoo.)   A, A,  unripe   fibres;    B,B, 
half-ripe  fibres;    C,  C,  fully-ripe  fibres. 


PHYSICAL   STRUCTURE  AND  PROPERTIES  OF  COTTON      247 

tions.  The  fibre  also  at  times  presents  the  appearance  of  a 
rather  smooth  flat  band  with  little  or  no  thickened  edges.  The 
twist  of  the  fibre  does  not  appear  to  be  continuous  in  one  direc- 
tion; a  portion  of  a  fibre  may  be  twisted  axially  to  the  right, 
then  exhibit  a  flattened  portion  without  any  twist  at  all,  then 
again  show  an  axial  twist  to  the  left.  The  twist  of  the  cotton 
fibre  appears  to  be  a  character  acquired  through  cultivation, 
as  it  is  not  possessed  by  wild  cotton.  Monie*  explains  the 
twist  in  cotton  as  follows:  The  rotary  motion  begins  with  the 
process  of  vacua tion  in  the  fibre,  caused  by  the  withdrawal 
of  some  of  the  fluid  in  the  fibre  when  the  seed  begins  to  ripen, 
and  as  this  is  affected  slowly  and  progressively,  beginning  at 
the  extremity  farthest  from  the  seed  and  gradually  receding 
towards  the  base,  the  free  end  or  point  becomes  twisted  on  its 
own  axis  several  times,  thus  producing  the  convoluted  form 
exhibited  under  the  microscope.  According  to  Hanausekf 
the  greater  the  number  of  twists  in  a  given  length  of  the  fibre 
and  the  greater  the  regularity  of  these  twists,  so  much  the 
greater  is  the  commercial  value  of  the  cotton.  The  correctness 
of  this  statement,  however,  is  disputed  by  Herbig.J  For 
about  three-fourths  of  its  length  the  fibre  maintains  a  com- 
paratively uniform  diameter,  then  it  gradually  tapers  to  a 
point,  where  it  is  perfectly  cylindrical  and  often  solid  (see 
Fig.  67) .  In  some  cases  portions  of  a  fibre  may  exhibit  cylindrical 
and  apparently  solid  spaces,  doubtless  caused  by  irregularities 
in  the  growth  of  tlw  cell.  At  these  places  the  strength  of  the 
fibre  is  weakened,  and  will  not  absorb  solutions  to  the  same 
degree  as  the  rest  of  the  fibre.  The  cell-wall  is  rather  thin 
and  the  lumen  occupies  about  two-thirds  of  the  entire  breadth 
and  shows  up  very  prominently  in  polarized  light.  Between 
its  thickened  edges  the  fibre  exhibits  the  appearance  of  a  finely 
granulated  surface.  Fibres  of  dead  cotton,  or  those  which 
have  not  reached  their  full  maturity,  are  seldom  twisted  spirally 
and  do  not  have  a  lumen,  but  are  thin,  transparent  bands 

*  The  Cotton  Fibre,  p.  25. 

t  Microscopy  of  Technical  Products,  p.  61. 

%Zeitschr.  ges.  Text.  Ind.,  1900,  pp.  17-19. 


248 


THE  TEXTILE  FIBRES 


(see  Fig.  65,  A).  Unripe  cotton  therefore  has  not  much  value 
for  purposes  of  manufacture,  as  it  contracts  and  curls  up  in  the 
warm  atmosphere  of  the  mill,  and  consequently  yarn  contain- 
ing much  unripe  fibre  depreciates  considerably. 

Microscopically  cotton  fibres  differ  considerably  among 
themselves,  but  in  general  may  be  divided  into  four  classes: 

(a)  Fibres  exhibiting  a  smooth,  straight,  flat  appearance 
with  no  suggestion  of  internal  structure.  These  include  imma- 
ture cotton  fibres  and  also  fibres  which  have  over-ripened.  The 
external  wall  of  the  fibre  is  very  thin  (see  Fig.  66,  B). 


FIG.  67. — Cotton  Fibre.     A,  middle  portions  of  fibre;  B,  points  or  ends  of  fibre. 


(b)  Fibres  exhibiting  a  normal  appearance  through  some 
portions    of    their    length,  and    in    other  parts  a  structure- 
less  appearance  as  in  (a).     These  may  be  termed  "  kempy  " 
fibres;   the  solid,  tubular  portion  of  the  fibre  is  particularly 
resistant    to    the    absorption    of    liquids    and    dyestuffs,    and 
consequently    remains   uncolored   while   the   rest   of   the  fibre 
is  dyed. 

(c)  Straight,  tubular  fibres  exhibiting  a  well-defined  internal 
structure   and   a   transparent   cell-wall   of   varying   thickness. 
Fibres  of  this  character  may  often  be  mistaken  under  the 
microscope  for  linen,  especially  if  the  cell-wall  is  thick.     The 
fibres  of  Gossypium  conglomeratum  are  especially  lia*ble  to  show 
this  form. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON      249 

(d)  Normal  structure  of  twisted,  band-like  form  (see  Fig. 

65,  O. 

In  cross-section*  the  immature  fibres  show  only  a  single 
line  with  no  structure  (see  Fig.  66,  ^4),  and  but  little  or  no 
indication  of  an  internal  opening.  The  mature  fibre  is  thicker 
in  cross-section  and  exhibits  a  central  opening  (see  Fig.  66, 
B  and  C). 

The  most  characteristic  of  the  microchemical  reactions 
for  cotton  is  that  with  ammoniacal  copper  solution,  previously 
described.  With  bleached  cotton  the  external  cuticle  may  be 


FIG.  68. — Root"  of  Cotton    Fibre.      (X3oo.)      Showing   the   irregular    fracture 
caused  by  the  fibre  being  torn  from  the  seed.    .(Micrograph  by  author.) 

absent,  and  hence  such  a  fibre  may  not  show  any  distension. 
With  iodin  and  sulphuric  acid  the  cotton  fibre  becomes  blue 

*  Cross-sections  of  the  cotton  fibre  may  be  prepared  by  arranging  a  number 
of  fibres  in  parallel  rows  in  glycerin-gum,  allowing  the  gum  to  harden  by  drying 
and  then  cutting  a  section  with  a  suitable  microtome.  The  glycerin-gum  is 
prepared  from  10  grams  of  gum  arabic,  10  c.c.  of  water,  and  40-50  drops  of 
glycerin.  The  sections  should  be  examined  in  water,  and  again  after  treatment 
with  iodin-sulphuric  acid  reagent.  This  causes  the  sections  to  swell  to  broadly 
elliptical  or  irregular  forms  without  altering  the  shape  of  the  lumen,  the  cell-wall 
is  colored  blue,  while  the  cuticle  which  is  distinctly  evident  as  a  delicate  line,  is 
colored  vellow,  as  are  also  the  cell-contents. 


250  THE  TEXTILE  FIBRES 

in  color,  though  the  cuticle  remains  colorless.  Tincture  of 
madder  gives  an  orange  color;  fuchsin  produces  a  red  color 
which  is  destroyed  by  the  addition  of  ammonia.  Flax  does 
not  show  this  latter  reaction,  hence  this  serves  as  a  chemical 
means  of  distinguishing  between  cotton  and  linen,  provided 
the  linen  is  unbleached.  Bleached  linen  shows  practically  no 
differences  from  cotton  in  its  chemical  tests.  Anhydrous 
stannic  chloride  gives  a  black  color  with  cotton,  and  sulphuric 
acid  dissolves  the  fibre  rapidly. 

5.  Physical   Properties;    Spinning   Qualities. — The  natural, 
spiral-like  twist*  present  in  the  cotton  fibre  causes  the  latter 
to   be   especially  adaptable    to  purposes  of    spinning.         The 
spinning  qualities  of   the    cotton    fibre,  however,   depend  not 
only    on    the    nature    and    amount    of    twist    which    causes 
the  individual  fibres  to  lock  themselves  firmly  together,  but 
also  on  the  length  and  fineness  of  staple.     These  three  qualities 
in  general  will  determine  the  character  and  fineness  of  yarn 
which  may  be  spun  from  any  sample  of  cotton.     Sea-island 
cotton  lends  itself  to  the  spinning*  of  very  fine  yarns,  being 
spun  to  even  300*5  (that  is,  300  hanks  of  840  yards  each  would 
weigh  i  pound),  and  in  an  experimental  manner  this  cotton  is 
said  to  have  been  spun  as  fine  as  2ooo's. 

6.  Tensile  Strength.— In  its  tensile  strength  cotton  stands 
between  silk  and  wool;   whereas,  in  elasticity,  it  is  considerably 
below  either  of  the  other  two  fibres.     The  breaking  strain  of 
cotton  will  vary  from  2.5  to  10  grams,  depending  on  the  fine- 
ness of  staple;    the  finer  the  fibre  the  less  will  be  its  breaking 
strain. 


*  Kuhn  (Die  Baumwolle,  p.  122)  states  that  wild  varieties  of  cotton  show  a 
decreased  number  and  uniformity  of  twists  than  cultivated  species,  and  the 
relapse  of  a  cultivated  variety  into  a  wild  state  is  always  accompanied  by  a 
lessened  development  of  twist  in  the  fibre.  Kuhn  is  of  the  opinion  that  in  the 
wild  plant  the  fibrillae  of  which  the  cell-wall  of  the  fibre  is  composed,  tend  to 
assume  a  more  spiral  formation,  which  causes  the  fibre  to  become  more  rigid  and 
less  elastic  and  prevents  the  production  of  twists.  Cultivation  tends  to  make 
the  constituent  fibrillae  assume  a  position  more  parallel  to  the  axis  of  the  fibre, 
which  makes  the  latter  more  elastic  so  that  it  more  readily  lends  itself  to  the 
formation  of  twists. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     251 


The  following  table  shows  the  results  of  experiments  on  the 
tensile  strength  of  different  varieties  of  cotton:* 


Cotton. 

Mean  breaking  Strain. 

Grains. 

Grams. 

Sea-island  (Edisto) 

83-9 
147.6 
127.2 
107.1 
100.6 
140.  2 
147-7 
104-5 
141.9 

163-7 

5-45 
9-59 
7.26 
6.96 

6-53 
9.11 
9.61 
6.79 
9.22 
'  10.64 

Queensland  

Egyptian 

Alaranham 

Bengal                 

Pernambuco 

New  Orleans  

Upland                      

Surat  (Dhollerah) 

Surat  (Comptah)  

The  full  tensile  strength  of  the  individual  fibre,  however, 
is  not  utilized  in  the  spun  yarn.  Single  yarns  will  give  only 
about  20  per  cent,  or  one-fifth,  of  the  breaking  strain  calculated 
from  the  strength  of  the  separate  fibres;  two-ply  yarns  give 
about  25  per  cent.  Herzfeldf  gives  the  following  table  show- 
ing the  strength  in  grams  of  single  cotton  yarns  of  different 
counts,  the  numbering  of  the  yarns  being  according  to  the 
metric  system: 

*  Lecomte  gives  the  following  table  showing  the  breaking  strain  of  various 
cotton  fibres. 

Cotton. 

New  Orleans 9 

Texas 6.6 

Peru  (harsh) 10.5 

Peru  (long,  silky) 4.1 

Sea-island 8 

Port-au-Prince 9.5 

Haiti 5.1 

Tahiti 4.9 

Egyptian  (brown) 7.6 

Bengal . 4 

Tinnevelly 3.2 

t  Yarns  and  Textile  Fabrics,  p.  95. 


252 


THE  TEXTILE  FIBRES 


No. 

Weak. 

Medium. 

Strong. 

Very 
Strong. 

No. 

Weak. 

Medium. 

Strong. 

Very 
Strong. 

4 

880 

IOOO 

1250 

32 

125 

170 

200 

250 

6 

670 

920 

1080 

1340 

34 

1  20 

1  60 

IOO 

2  2O 

8 

500 

690 

810 

IOOO 

36 

no 

150 

1  80 

210 

10 

400 

550 

650 

800 

38 

i°5 

140 

170 

2OO 

12 

330 

460 

540 

660 

40 

IOO 

135 

1  60 

190 

14 

285 

390 

460 

570 

50 



no 

130 

140 

16 

250 

34° 

400 

500 

60 



90 

no 

125 

18 

22O 

300 

160 

440 

7o 

80 

oo 

IOS 

20 

2OO 

280 

32O 

400 

80 

70 

80 

or 

22 

1  80 

2  SO 

2Q< 

360 

QO 

60 

7O 

8s 

24 

I7O 

230 

270 

33° 

1  IOO 

cc 

6s 

80 

26 

ISO 

2IO 

2  so 

310 

no 

eo 

60 

70 

28 

I4O 

2OO 

230 

2QO 

!  1  20 

AC 

c  e 

60 

30 

130 

1  80 

215 

260 

Monie*  also  gives  a  table  showing  the  strength  of  cotton 
fibres  after  manufacture  into  yarn  in  relation  to  those  in  their 
natural  condition. 

CARDED  COTTON 


Average 

Test 

Number 
of 

Strength 
of 

Calcu- 
lated 

Actual 

Percent- 

Description of  Yarn. 

Fibres 
in  Cross- 
section 

Each 
Fibre 
in 

Strength 
of  Yarn 
in  Lbs. 

Strength 
of  Yarn 
in  Lbs. 

age  of 
Strength 
Utilized. 

of  Yarn. 

Grains. 

32*5  twist  American  cotton  

1  2O 

140 

2OO 

49-5 

24.7 

36's     "            "             "       

IIO 

140 

I76 

40.0 

22.7 

4o's     " 

IOO 

140 

1  60 

36.0 

22.5 

46*5     '  '     Egyptian  cotton  

132 

146 

2  2O 

52.0 

23-6 

,      «           «             « 

IIO 

146 

184 

4.6    O 

2  e   o 

y  ° 
6o's     "            "             "     

IOO 

146 

i  Oif. 

I67 

T-w  •  w 

33-5 

*3  •  ** 
20.6 

7o's     '  '     brown  Egyptian  cotton 

74 

150 

127 

27-5 

21.6 

8o's     " 

60 

ISO 

103 

23-5 

22.8 

COMBED  COTTON 


1  8o's  twist,  Egyptian  cotton.  .  .  . 

90 

1  20 

IOO 

25 

20.3 

I20'S       "               "               " 

e  r 

1  20 

66 

18 

24.    2 

I20'S       "               "               "        

SO 

1  20 

68 

15 

22.  0 

I4VS      "               "              " 

4O 

1  20 

e  t 

1  3 

21    6 

165*3     "      Sea-island  cotton  ... 

45 

IOO 

55 

13 

25-4 

IQO'S     "             "             "      ... 

38 

IOO 

43 

io-5 

24.4 

The  Cotton  Fibre. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     253 


The  following  table  exhibits  the  comparative  values  of  the 
tensile  strength  of  different  fibres.  The  "  breaking  length  " 
refers  to  a  length  of  thread  which  will  break  by  reason  of  its 
own  weight. 


Fibre. 

Breaking  Length 
in  Kilometres. 

Tensile  Strength, 
Kilograms  per 
Square  mm. 

Cotton        

25.0 

37-6 

Wool 

8.3 

10.9 

Raw  silk 

3^    O 

44.8 

Flax  fibres  
Tute 

24.0 

20.  o 

35-2 
28.7 

Ramie 

20  o 

28.7 

Hemp        

30.0 

45.0 

Manila  hemp        

31.8 

47  •  7 

Cocoanut   fibre  

17.8 

29.2 

Vegetable  silk  

24.5 

35.9 

The  following  table  shows  the  breaking  length  and  correspond- 
ing elasticity  (elongation  sustained  under  the  breaking  strain) 
of  yarns  from  various  fibres: 


Yarn. 

Breaking  Length 
in  Kilometres. 

Elasticity. 

Cotton  yarn  

13-14 

3.97 

Ramie  yarn    

II—  12 

0.8-1.8 

Flax  yarn  (wet  spun)  .... 
"       "     (dry  spun)  .... 
Jute  yarn  
Artificial  silk 

12-20 
11-12 

99 

12    O 

1.1-1.8 
2-5-3-7 

2.O 
2    O 

Wood  pulp  yarn  (Silvalin). 

5-5 

6.8 

7.  Method  of  Determining  Tensile  Strength  of  Fibres. — There 
have  been  a  number  of  machines  devised  for  the  purpose  of 
determining  the  tensile  strength  and  elasticity  of  fabrics  and 
yarns,  and  a  few  instruments  have  also  been  adapted  for  the 
testing  of  single  fibres.  As  the  individual  fibre,  however,  is 
a  very  slender  and  delicate  object,  especially  in  the  case  of 
certain  vegetable  fibres,  the  determination  of  its  physical 
factors  is  an  operation  which  requires  a  delicately  adjusted 
apparatus.  In  machines  which  require  the  taking  on  or  off 


254 


THE  TEXTILE   FIBRES 


of  weights,  the  jar  is  usually  sufficient  to  break  the  fibre  before 
its  true  breaking  strain  is  reached.  The  same  criticism  is  also 
true  for  machines  employing  water  as  a  weight.  A  machine 
devised  by  the  author  has  proved  very  satisfactory  for  determin- 
ing the  tensile  strength  and  elasticity  of  almost  any  fibre, 
from  very  fine  and  delicate  filaments  to  coarse  and  strong 
hairs.  A  diagrammatic  drawing  of  this  machine  is  given  in 
Fig.  69.  The  fibre  to  be  tested  is  clamped  between  the  jaws 


FIG.  69. — Fibre-testing  Machine. 

/,  jaws  with  screw-clamps  for  holding  the  fibre;  the  lower  jaw  may  be  raised  or 
lowered;  /?,  sliding-rod  working  on  a  rack  and  pinion;  this  takes  the  place 
of  weights;  G,  wheel  graduated  on  its  face  in  decigrams,  moving  on  the 
same  axis  as  the  pinion  for  sliding  the  weight;  T,  thumb-screw  for  turning 
the  small  shaft  working  the  pinion  at  P;  W,  counterbalancing  weight  for 
regulating  the  zero-point  of  the  machine;  S,  scale  for  reading  the  stretch  of 
the  fibre.  (Drawing  bv  author.) 


at  (J),  the  pointer  attached  to  the  end  of  the  beam  above  the 
upper  jaw  being  brought  to  the  zero-mark  on  the  scale  (S), 
while  the  lower  jaw  is  raised  or  lowered  in  its  stand  until  the 
desired  distance  between  the  jaws  is  obtained.  To  obtain 
comparable  results  this  distance  should  always  be  the  same; 
and  10  cm.,  in  the  case  of  long  fibres,  or  2  cm.  for  short  fibres, 
have  proved  to  be  good  lengths  of  fibre  to  test.  The  sliding- 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     255 

bar  (R)  is  moved  forward  by  turning  the  rod  (J1),  which  moves 
the  rack  and  pinion  at  (P),  until  the  graduation  on  the  wheel 
(G)  is  at  zero  to  the  indicator.  Under  these  conditions  there 
is  no  strain  on  the  fibre.  A  stretching  force  is  then  placed  on 
the  fibre  by  moving  the  bar  (R)  backward  by  turning  the  rod 
(r);  the  motion  of  this  bar  is  made  uniform  and  gradual  until 
the  fibre  finally  breaks  under  the  strain  thus  placed  upon  it. 
The  graduation  on  the  wheel  (G)  will  then  indicate  in  decigrams 
the  breaking  strain  of  the  fibre  being  tested.  The  elasticity 
is  obtained  by  watching  carefully  the  pointer  moving  up  the 
scale  of  millimeters  at  (S)  until  the  rupture  of  the  fibre  takes 
place;  the  distance  this  pointer  moves  represents  the  actual 
stretch  of  the  fibre,  and  if  the  length  of  fibre  taken  between  the 
jaws  is  10  cm.,  this  figure  will  represent  directly  the  percentage 
of  elasticity.  If  the  length  of  fibre  taken  is  only  2  cm.,  to 
obtain  the  percentage  of  elasticity  it  is  necessary  to  multiply 
the  amount  of  stretch  in  millimeters  by  five;  and  for  other 
lengths  of  fibre  similar  proportions  will  hold.  The  weight  (W) 
at  the  rear  end  of  the  beam  can  be  moved  backward  or  forward, 
and  is  for  the  purpose  of  adjusting  the  balance  so  that  there  is 
no  strain  at  (/)  when  the  indicator  on  (G)  marks  zero.  The 
wheel  (G)  is  graduated  in  decigrams,  and  this  marks  the 
sensibility  of  the  machine;  the  total  graduations  on  (G)  running 
from  zero  to  400.  When  fibres  are  tested  having  a  greater 
tensile  strength  than  400  decigrams  a  fixed  additional  weight 
of  10,  25,  50,  etc.,  grams  may  be  hung  from  (W),  and  this 
must  be  added  to  the  reading  on  the  wheel  when  the  fibre  breaks. 
If  the  elasticity  of  the  fibre  is  so  great  as  to  carry  the  pointer 
beyond  the  limits  of  the  scale  at  (5),  a  shorter  length  of  fibre 
must  be  tested.  A  fair  average  of  breaking  strain  and  elasticity 
may  be  obtained  for  any  quality  of  fibre  by  testing  about  10 
separate  fibres  and  taking  a  mean  of  the  total  tests.  If  the 
quality  of  the  fibres,  however,  in  a  sample  does  not  run  very 
uniform,  it  is  best  to  increase  the  number  of  tests  to  25  or 
even  50  in  order  that  a  satisfactory  average  may  be  obtained. 
8.  Hygroscopic  Quality. — Cotton  is  less  hygroscopic  than 
either  wool  or  silk ;  under  normal  conditions  it  will  contain  from 


256 


THE  TEXTILE  FIBRES 


5  to  8  per  cent  of  hygroscopic  moisture,*  though  in  a  very 
moist  atmosphere  this  may  be  considerably  increased,  f 

*  Kuhn  (Die  Baumwolle,  p.  131)  states  that  a  portion  of  this  moisture  must 
be  regarded  as  a  constituent  part  of  the  fibre.  This  water  of  constitution,  he 
states,  amounts  to  about  2  per  cent.  It  can  be  expelled  at  over  105°  C.,  and 
the  fibre  then  becomes  harsh  and  brittle,  and  loses  its  elasticity.  This  state- 
ment concerning  water  of  constitution,  however,  demands  further  investigation 
before  it  can  be  unreservedly  accepted  as  a  fact. 

f  The  following  table  shows  the  results  of  a  series  of  tests  to  determine  the 
hygroscopic  moisture  in  various  grades  of  cotton: 


Grade. 

Per  Cent  of  Moisture. 

Maximum. 

Minimum. 

Average. 

North  American.  • 

South  American  . 
Roryntian 

'  Texas   

14.8 

9-9 
9-8 

9-9 
16.2 
10.3 
8.9 

8.1 

8-3 
n.  8 
9.8 

9-5 
10.8 

8-7 

7-7 
8.1 

8.2 

7-9 

6.9 
7.8 
7-i 
7-4 
10.7 

8-4 

7-2 

9-2 
9-7  . 

.  ;:"'?    94 

9.6 
13.8 

9-4 
8-7 

8.1 
8-3 
9-5 
9.1 

8.4 
9-3 
8-5 

75 
7-o 

8.2 

7-9 

Orleans  
Memphis  
Sea-island  
Savannah  

Norfolk  

Florida 

Maceio  
Paraiba  
Brazil  

7-3 
7-5 

6.8 

7-i 

7-8 

6.2 

6-4 

Peru 

[Ashmouni  
Gallini  
Brown    

Indian 

Surat  
Dhollerah 

Bengal  

Tinnevelly  

Beltzer  (Les  Matieres  Cellulosiques}  states  that  Indian  cottons  under  the  same 
atmospheric  conditions  absorb  about  1.5  per  cent  more  of  moisture  than  American 
cottons,  though  this  difference  is  only  manifested  within  certain  limits  as  to 
the  saturation  of  the  air  with  water  vapor;  when  the  relative  humidity  is  50 
per  cent  the  difference  in  the  amount  absorbed  is  only  i  per  cent.  Egyptian 
cotton  is  said  to  occupy  an  intermediate  position  between  Indian  and  American 
cottons.  In  the  absence  of  definite  data  in  this  respect,  however,  the  present 
author  is  inclined  to  question  the  conclusions  of  Beltzer. 


PHYSICAL  STRUCTURE  AND  PROPERTIES  OF  COTTON     257 


The  hygroscopic  quality  of  cotton  (and,  in  fact,  of  any  other 
vegetable  fibre  as  well)  has  much  to  do  with  its  proper  condi- 
tion during  the  various  processes  of  spinning  and  finishing, 
ing.  It  also  has  an  influence  on  the  commercial  valuation 
of  the  raw  material,  as  the  amount  of  hygroscopic  moisture 
varies  with  atmospheric  conditions,  and  it  is  important  to  have 
a  normal  standard  of  reference.*  Its  influence  on  spinning 
is  even  greater,  and  proper  conditions  of  atmospheric  moisture 
must  be  maintained  in  the  spinning-room  in  order  to  achieve 
the  best  results.!  The  spinning  properties  of  raw  cotton,  how- 
ever, are  also  affected  by  other  substances  associated  with  the 
cellulose  of  the  fibre,  but  it  is  without  question  that  the  physical 
condition  of  cotton  is  largely  influenced  by  its  content  of  hygro- 
scopic moisture,  and  this  should  be  delicately  adjusted  by  the 
spinner  to  meet  the  conditions  of  his  work.  The  mechanical 

*  The  amount  of  "regain"  allowed  in  the  conditioning  of  cotton  on  the  con- 
tinent of  Europe  is  8£  per  cent.  The  following  table  by  Hartshorne  gives 
the  " regain"  of  cotton  for  various  temperatures  and  humidities: 

TABLE  OF  REGAIN  FOR  COTTON  AT  VARIOUS  TEMPERATURES  AND  PERCENTAGES 

OF  HUMIDITY 


Degrees  Fahrenheit. 

Percentage 

Humidity. 

SO. 

60. 

70. 

80. 

90. 

100. 

40 

5-90 

5-79 

5.65 

5-47 

5-25 

5-05 

50 

6.89 

6.78 

6.63 

6.45 

6.18 

5-86 

60 

8.00 

7.87 

7.69 

7-44 

7-13 

6.80 

70 

9.14 

9.00 

8.79 

8.58 

8.32 

8.05 

80 

10.58 

10.42 

10.23 

9-95 

9.70 

9.60 

90 

12.28 

12.  IO 

H.85 

ii  .56 

11-43 

11.85 

ICO 

14.12 

I4.OO 

13.80 

13-65 

13.70 

14-50 

t  The  temperature  and  percentage  of  humidity  suitable  for  various  depart- 
ments of  a  cotton  mill  vary  with  the  nature  of  the  process  and  the  fineness  of  the 
yarn.  The  finer  the  yarn  the  higher  should  be  the  humidity.  The  following 
table  represents  the  general  practice: 

Humidity, 
Per  Cent. 

Card-room 60-65  7°~75 

Spinning-room 60-75  75~8o 

Weaving  shed 75~8o  70-75 


Temperature, 
Deg.  Fahr. 


258  THE  TEXTILE  FIBRES 

treatment  of  woven  textile  materials  in  finishing  processes, 
such  as  mangling,  beetling,  calendering,  etc.,  is  also  dependent 
for  good  results  to  quite  an  extent  on  the  hygroscopic  condi- 
tion of  the  fibre,*  hence  the  amount  of  moisture  present  during 
the  finishing  operations,  together  with  the  method  and  degree 
of  drying,  should  be  carefully  studied.! 

In  testing  the  influence  of  moisture  on  the  strength  of  cotton 
material,  the  Industrial  Society  of  Mulhouse  reports  as  follows: 

Normal  strength  of  cloth 100 

Saturated  with  moisture 104 

Dried  on  hot  cylinder 86 

Again  dampened 103 

It  would  appear  from  these  results  that  the  alternate  moistening 
and  hot  drying  of  cotton  caused  little  or  no  deterioration  in  its 
strength. 

When  cotton  is  purified  from  its  adhering  waxy  and  fatty 
matters,  it  becomes  remarkably  absorbent. J  This  quality  is 

*  Thomson  has  pointed  out  the  effect  of  moisture  on  the  strength  of  cotton 
yarn  in  finishing.  He  gives  the  following  figures: 

Moisture  in  Yarn,  Breaking 

Per  Cent.  Strain. 

2  . 89  (dry) 39-9 

8 . 93  (usual) 64 .  o 

17.36  (moist) 69 .  2 

Other  investigators  have  substantiated  these  results.  The  increase  in  elas- 
ticity of  moist  yarn  over  dry  yarn  is  about  25  per  cent,  while  the  increase  in  strength 
is  about  10  per  cent. 

f  Cotton  may  combine  with  water  in  two  forms:  (i)  as  hygroscopic 
moisture  and  (2)  as  water  of  hydration.  The  hygroscopic  moisture  is  that  absorbed 
from  moist  air,  and  varies  in  quantity  from  8  to  12  per  cent,  depending  on  the 
temperature  and  humidity  of  the  air.  This  water  is  completely  eliminated  by 
heating  the  cotton  to  220°  F.,  and  the  cotton  may  then  be  termed  " desiccated." 
The  water  of  hydration  is  only  separated  at  a  higher  temperature,  320°  to  350°  F. 
being  necessary.  At  these  temperatures  a  further  loss  in  weight  of  i  to  3  per 
cent  is  obtained.  The  water  of  hydration  may  also  be  estimated  by  first  desic- 
cating the  cellulose  at  220°  F.,  then  boiling  in  toluene  and  distilling.  Cotton 
containing  water  of  hydration  is  known  as  cellulose  hydrate  or  hydracellulose. 
The  limit  of  the  hydration  in  cotton  may  be  considered  as  corresponding  to 
mercerized  cotton,  Ci2H2oOio-H2O  (see  Cellulose  Hydrate).  These  statements, 
however,  need  further  experimental  data  to  confirm  their  accuracy, 

t  When  properly  prepared,  absorbent  cotton  should  absorb  18  times  its  own 
weight  of  water. 


PHYSICAL   STRUCTURE  AND   PROPERTIES  OF  COTTON     259 

explained  on  the  supposition  that  the  ripe  cotton  fibre  is  made 
up  of  a  series  of  tissues  of  cellulose,  separated  from  each  other 
by  intercellular  matter,  in  this  way  forming  a  series  of  capillary 
surfaces  which  are  capable  of  exerting  considerable  capillary 
force  upon  any  liquid  in  which  the  fibre  may  be  immersed. 
Dry  cotton  also  appears  to  be  remarkably  absorptive  of  gases; 
it  is  said  that  the  fibre  can  absorb  115  times  its  volume  of 
ammonia  at  the  ordinary  atmospheric  pressure. 

The  following  accurate  method  of  determining  the  amount 
of  hygroscopic  water  in  cotton  (or  other  cellulose  fibre)  has 
been  suggested  by  C.  Schwalbe.*  About  3  grams  of  the  material 
is  boiled  with  300-500  c.c.  of  pure  toluene  which  has  a  boiling- 
point  of  about  230°  F.  The  water  is  collected  by  distillation 
in  a  graduated  tube  and  from  a  determination  of  its  volume  or 
by  weighing,  the  percentage  of  moisture  may  be  calculated. 
This  method  is  applicable  to  the  determination  of  moisture 
in  mercerized  cotton  and  hydra  ted  celluloses  (artificial  silk). 
The  following  gives  the  amount  of  moisture  as  determined  in 
this  manner  with  different  materials: 

Per  Cent. 

Paper  made  from  cotton 6.5 

Vegetable  silk 6.7 

Mercerized  cotton 9-25 

wood  pulp 10 . 25 

Viscose  silk 11.25 

Cotton  which  has  been  deprived  of  its  hygroscopic  moisture 
by  drying  in  an  oven  at  212°  to  220°  F.  by  the  usual  method, 
easily  regains  its  original  amount  of  moisture  after  10-12  hours 
exposure  to  the  air.  When  the  moisture  has  been  removed  by 
boiling  toluene,  however,  the  regain  in  moisture  is  somewhat 
less,  on  account  of  the  impregnation  of  the  fibres.  When 
the  drying  operation  is  conducted  at  too  high  a  temperature 
the  regain  of  moisture  is  also  less,  so  that  the  normal  regain 
of  moisture  may  be  taken  as  the  exact  measure  of  the  hygro- 
scopic moisture,  without  the  elimination  of  the  water  of  hydra- 
tion. 

*  Schwalbe,  Zeil.  angew.  Chemie,  1908,  p.  1321. 


CHAPTER  XII 

CHEMICAL  PROPERTIES  OF  COTTON;  CELLULOSE 

1.  Chemical   Constitution. — In     its     chemical    composition 
cotton,  in  common  with  the  other  vegetable  fibres,   consists 
essentially  of  cellulose.*    On  the  surface  there  is  a  protecting 
layer  of  wax  and  oily  matter,  and  also  in  the  fibre  there  is 
a  trace  of  pigment,  which  in  some  varieties  of  cotton  becomes 
quite   emphasized.     The  removal  of    these  substances  is   the 
object  of  the  boiling-out  and  bleaching  process  to  which  cotton 
is  subjected  prior  to  its  dyeing  and  printing.     In  reality  the 
purified  cotton  fibre  as  it  exists  in  bleached  material  is  prac- 
tically pure  cellulose,  and  this  compound  alone  appears  to  be 
essential  to  its  structural  organization. 

2.  Impurities   in   Cotton. — The  natural    impurities  present 
in  the  raw  cotton  fibre  amount  to  about  4  to  5  per  cent,  and 
consist    chiefly    of  pec  tic  acid,    coloring  matter,    cot  ton- wax, 
cotton-oil,    and    albuminous    matter.     The    fibre    gives    about 
i  per  cent  of  ash  on  ignition.     Bowman  is  of  the  opinion  that 
considerable  stress  should  be  laid  on  the  fact  that  the  cotton 
fibre  contains  about  i  per  cent  of  mineral  matter  as  an  integral 
part  of  its  constitution,  and  this  no  doubt  has  considerable 
influence   on   its    structure   and   properties.     The    oil  present 
in  the  fibre  appears  to  be  identical  with  cottonseed-oil,  and  is 

*  The  cellulose  of  cotton  is  of  very  constant  composition  and  easy  to  purify. 
It  is  termed  normal  cellulose  to  distinguish  it  from  other  types  of  cellulose  present 
in  many  other  vegetable  fibres  where  the  cellulose  is  in  combination  with  pectin 
(linen  type)  and  lignin  (jute  type). 

260 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     261 

probably  obtained  from  the  seed  to  which  the  fibre  is  attached. 
The  cotton- wax  serves  as  a  protective  coating  for  the  fibre  and 
makes  it  water-repellent,  as  is  evidenced  by  the  long  time  it 
requires  for  raw  cotton  to  be  wetted  out  by  simply  steeping  in 
water.  This  wax  appears  to  be  closely  analogous  to  carnaiiba 
wax;  it  is  not  soluble  in  alkalies,  though  it  may  be  gradually 
emulsified  by  a  long-continued  boiling  in  alkaline  solutions, 
on  which  fact  is  based  the  "  boiling-out  "  of  cotton  by  the 
ordinary  methods.  Cotton-wax,  however,  appears  to  be  readily 
soluble  in  sulphated  oils,  such  as  Turkey-red  oil,  and  hence 
cotton  may  be  rapidly  and  thoroughly  wetted  out  by  using  a 
solution  of  such  an  oil.  The  coating  of  wax  over  the  cotton 
fibre  appears  to  influence  its  spinning  qualities  to  a  certain 
extent,  as  it  requires,  for  instance,  a  rather  elevated  tem- 
perature to  successfully  spin  fine  yarns,  in  order  probably  to 
soften  the  waxy  coating  of  the  fibre.*  The  fatty  acid  present 
in  cotton-wax  has  been  found  to  be  identical  with  margaric 
acid.  According  to  Dr.  Schunck,  American  cotton  contains 
about  0.84  per  cent  of  fatty  matters,  whereas  East  Indian 
cotton  contains  only  0.337  Per  cent. 

Analysis  of  cotton-wax  shows  it  to  consist  of  the  following: 


Per  Cent. 

Carbon 80 . 38 

Hydrogen 14 . 51 

Oxygen 5.11 


It  fuses  at  85.9°  C.,  and  solidifies  at  82°  C.,  hence  it  bears  a 
close  analogy  to  both  cerosin,  or  sugar-cane  wax,  and  carnaiiba 
wax. 


*  As  the  temperature  falls  the  oily  wax  tends  to  become  stiff  and  gummy 
and  prevents  the  proper  drawing  of  the  fibre  in  spinning.  Its  presence  among  the 
thin  laminations  of  the  cell-walls  gives  a  greater  elasticity  to  the  fibre,  and  renders 
it  less  liable  to  sudden  rupture.  The  gradual  drying  up  of  the  more  volatile 
portions  of  this  oil  in  the  fibre,  leaving  the  remaining  portion  thicker  and  stiffer, 
may  also,  and  probably  does,  account  for  the  fact,  noticed  by  most  spinners,  that 
new  crop  cotton  seems  to  work  better  and  makes  less  waste  than  cotton  harvested 
as  the  season  advances.  (Bowman,  Cotton  Fibre,  p.  55.) 


262  THE  TEXTILE  FIBRES 

The  following  table  gives  the  analysis  of  the  cotton  fibre 
from  reports  of  the  U.  S.  Department  of  Agriculture,*  represent- 
ing the  average  of  a  large  number  of  tests: 

Per  Cent. 

Water 6 . 74 

Ash 1.65 

Protein 1.50 

Fibre  (cellulose) 83 . 71 

Nitrogen-free  extract 5 . 79 

Fat o .  61 

The  composition  of  cotton  fibres  from  different  sources  may 
be  said  to  be  practically  the  same,  as  variations  in  the  re- 
ported analyses  are  no  greater  than  the  variations  to  be  ob- 
served in  the  analyses  of  different  samples  of  the  same  kind 
of  cotton. 

Lester  f  has  studied  the  substances  present  in  raw  cotton 
capable  of  extraction  by  water.  J  This  extract  is  evidently 

*  See  Bulletin  No.  33.  An  analysis  of  the  fertilizing  constituents  present  in 
the  cotton  fibre  is  as  follows: 

FERTILIZING  CONSTITUENTS 

Per  Cent. 

Water 6.07 

Ash .N 1.37 

Nitrogen o .  34 

Phosphoric  acid o .  10 

Potash o .  46 

Soda o .  09 

Lime o.  19 

Magnesia o .  08 

Ferric  oxide 0.02 

Sulphuric  acid o .  60 

Chlorin 0.07 

Insoluble  matter o .  05 

t  Jour.  Soc.  Chem.  Ind.,  vol.  21,  p.  388. 

J  The  complete  chemical  analysis  of  cotton  may  be  conducted  as  follows: 
First,  the  hygroscopic  moisture  may  be  determined  by  drying  at  220°  F.  (or  by 
the  toluene  method  of  Schwalbe,  see  p.  259);  second,  a  weighed  portion  of  the 
fibre  is  incinerated  in  a  platinum  or  porcelain  crucible  to  a  complete  ash;  this 
will  give  the  ash  of  the  raw  fibre,  and  it  may  be  subsequently  analyzed  by  the 
customary  chemical  methods  in  order  to  ascertain  its  composition.  Another 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     263 

of  a  complex  nature  and  amounts  to  about  1.73  per  cent  from 
yarn,  though  if  the  cotton  yarn  is  cut  up  into  short  lengths 
(i  inch)  the  extractive  matter  rises  to  2.11  per  cent.  The 
analysis  of  this  extract  is  given  as  follows: 

Per  Cent. 

Ash 39 •  22 

Fatty  acids  (by  HC1) -  ,  ....  62 .30 

Ether  extract i?-S2 

Cold  water  extract 39 . 50 

Ash  of  original  cotton 0.82 

Ash  of  cotton  after  extraction  with  water 0.21 

Lester  also  shows  that  while  cotton  on  exposure  to  the  air 
after  drying  will  reabsorb  about  8  per  cent  of  moisture,  the 
dried  aqueous  extract  from  cotton  will  absorb  about  32  per 
cent,  and  hence  is  of  a  far  different  nature  from  that  of  cotton. 


portion  of  the  fibre  is  boiled  with  caustic  soda  solution  of  2°  Tw.,  rinsed,  and 
dried;  the  loss  in  weight  is  considered  as  fat  and  wax.  Or  the  fibres  may  be 
extracted  with  alcohol  and  ether  in  a  Soxhlet  apparatus,  and  the  extractive 
matter  determined  by  loss  in  weight,  or  ascertained  directly  by  evaporation  of 
the  solvent.  The  amount  of  nitrogen  in  the  cotton  may  be  determined  by 
Kjehldahl's  method.  The  amount  of  cuticle  by  determining  the  loss  in  weight, 
after  boiling  with  sodium  sulphite  solution.  The  ash  of  the  remaining  cellulose 
can  then  be  determined.  A  resume  of  the  complete  analysis  of  cotton  is  as 
follows: 

(a)  Dry  at  220°  F.  =  hygroscopic  moisture. 

(6)  Ignite  =  ash  of  raw  fibre. 

(c)  Boil  with  caustic  soda  =  fat  and  wax. 

(d)  Bleach  with  sodium  hypochlorite  solution  =  coloring  matters. 

(<?)   Boil  with  alkaline  solution  of  sodium  sulphite  =  cuticular  substance. 

(/)    Ignite  =  loss  is  cellulose. 

(g)  Residue  of  ignition  =  ash  of  cellulose. 

Such  an  analysis  will  furnish  about  the  following  results: 

Per  Cent. 

(a)  Hygroscopic  water 7 .  oo 

(6)  Ash  of  raw  fibre 1.12 

(c)  Fats  and  wax 5 .  oo 

(d )  Loss  in  bleaching o .  50 

(e)  Cuticular  matters o. 75 

(/)  Pure  cellulose 86 . 63 

(g)  Ash  of  cellulose 0.12 


264 


THE  TEXTILE  FIBRES 


Probably  raw  cotton  owes  some  of  its  hygroscopic  moisture 
to  this  substance. 

The  coloring  matter  of  cotton  has  been  investigated  and 
has  been  found  to  consist  of  two  organic  pigments,*  the  one 
easily  soluble  in  alcohol  and  the  other  dissolved  only  by  boiling 
alcohol.  According  to  Schunck,|  the  composition  of  these 
bodies  from  Nankin  cotton  is  as  follows : 


A.  Soluble  in 
Cold  Alcohol, 
Per  Cent. 

B.   Insoluble  in 
Cold  Alcohol 
Per  Cent. 

Carbon  

58.22 

57-7° 

Hydrogen  .    .  . 

<      42 

5   60 

Nitrogen  

3  •  73 

4  99 

Oxygen  

32  63 

S1   71 

The  composition  of  the  analogous  coloring  matters  in  American 
cotton  is  practically  identical  with  the  above.  { 

Pectin  compounds  form  the  greater  portion  of  the  impurities 
present  in  cotton,  and  are  probably  rather  complex  in 
nature. 

The  quantity  of  ash  (mineral  matter)  in  raw  bale-cotton  will 
average  considerably  higher  than  that  obtained  from  the  purified 
fibre;  this  is  due  to  adhering  sand  and  dust  which  are  nearly 


*  There  is  a  peculiar  variety  of  peeler  cotton  known  as  "blue  bender"  cotton. 
This  fibre  is  characterized  by  a  bluish  color  which  cannot  be  bleached  out  by 
the  usual  methods  employed  for  the  bleaching  of  ordinary  cotton.  It  receives 
its  name  from  occurring  in  the  "bends"  of  the  Mississippi  River  valley.  The 
exact  nature  of  the  color  and  the  cause  of  its  formation  in  this  variety  of  cotton 
are  not  known.  By  some  it  is  supposed  that  the  defect  arises  from  the  plant  being 
touched  by  frost  too  early,  while  others  assume  that  the  cause  is  to  be  found  in 
some  ingredient  in  the  soil.  Outside  of  its  defective  color  and  resistance  to 
bleaching,  the  appearance  and  quality  of  the  fibre  are  otherwise  unimpaired. 

t  Chem.  News,  1868,  p.  118;  1874,  p.  5. 

|  It  is  a  common  opinion  that  brownish  colored  cottons  contain  more  iron 
than  lighter  colored  varieties.  It  appears,  however,  that  the  ash  of  dark  colored 
cottons  does  not  contain  a  greater  proportion  of  iron.  The  coloring  matter  is 
altogether  an  organic  pigment.  Also  see  Kuhn,  Die  Baumwolle,  p.  138. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     265 


always  present.     The  following  table  shows  the  amount  of  ash 
contained  in  samples  of  different  varieties  of  cotton:* 

Per  Cent. 

Dharwar 4.16 

Dhollerah 6.22 

Sea-island 1.25 

Peruvian  (soft) i .  68 

' '         (rough) 1.15 

Bengal 3 .98 

Broach 3 . 14 

Oomrawuttee 2.52 

Egyptian  (brown) i .  73 

' '         (white) 1.19 

Pernambuco i .  60 

American 1.52 

When  the  amount  of  ash  is  found  to  be  much  over  one  per 
cent,  the  excess  may  be  considered  as  mechanically  attached 
sand  and  dust.f  The  true  ash  of  the  cotton  fibre  consists 

*  Monie  (The  Cotton  Fibre)  gives  a  table  showing  the  percentage  of  sand  or 
mineral  matter  contained  in  bales  of  commercial  cotton  as  they  arrive  at  Liverpool 


Pe 


Sea-island 

Rough  Peruvian 

Gallini  Egyptian 

Brown  Egyptian 

Orleans 

White  Egyptian 

Smooth  Peruvian 

Pernambuco.  . 


Cent. 


Per  Cent. 

Upland 2 . 10 

Bahia 2. 16 

Hingunghat 2 . 33 

Broach 2 . 58 

Oomrawuttee 2 . 93 

African 3 . 20 

Dhollerah 4.10 

Comptah 4.18 

Bengal 5 . 30 

It  is  to  be  presumed  that  Monie  did  not  include  in  the  above  figures  the  amount 

of  mineral  matter  in  cotton  as  obtained  from  the  ash  of  the  purified  fibre,  but 

that  his  figures  represent  the  sand  or  other  foreign  mineral  matter  mechanically 

held  in  the  baled  cotton. 

f  Mitchell  &  Prideaux  (Fibres  Used  in  Textile  Industries,  p.  96)  give  analyses 

of  typical  specimens  of  cotton,  as  follows: 


.  10 
•25 
•25 
.60 
.60 

•75 
.80 
.98 


Texas .  .  .2.10 


Variety  of  Cotton. 

Moisture. 
Per  Cent. 

Mineral  Matter. 
Including  Sand. 
Per  Cent. 

Phosphoric  Acid 
as  P2O4. 
Per  Cent. 

Sea-island  
Orleans  

7.83 
7    7O 

2.  21 
2   CX 

O.22 

o.i8 

Pernambuco         .             .    . 

8  85 

2   08 

o  37 

Indian  (Oomaa) 

7    27 

2    86 

O    2\ 

Indian  (Bengal)  

7.89 

T,  .  3O 

0.15 

266  THE  TEXTILE  FIBRES 

principally  of  the  carbonates,  phosphates,*  chlorides,  and 
sulphates  of  potassium,  calcium,  and  magnesium,  as  is  exhibited 
by  the  following  analysis  of  Dr.  Ure: 

Per  Cent. 

Potassium  carbonate 44 . 80 

chloride 9 . 90 

sulphate 9 .30 

Calcium  phosphate 9 .  oo 

' '        carbonate .  . 10 . 60 

Magnesium  phosphate 8 . 40 

Ferric  oxide 3 .  oo 

Alumina  and  loss 5 .  oo 

The  analyses  of  Davis,  Dreyfus,  and  Holland,  reported  as 
a  mean  from  twelve  different  varieties  of  cotton,  show  a  little 
difference  from  the  above  analysis,  especially  in  having  present 
sodium  carbonate  as  one  of  the  constituents.  The  mean  of 
these  analyses  is  given  as  follows: 

Per  Cent. 

Potassium  carbonate 33 . 22 

"         chloride 10.21 

sulphate , 13 .02 

Sodium  carbonate 3.35 

Magnesium  phosphate 8 . 73 

carbonate 7.81 

Calcium  carbonate v 20 . 26 

Ferric  oxide  f 3  40 

The  albuminous  or  nitrogenous  matter  present  in  cotton 
is  only  of  very  small  amount,  and  doubtless  consists  of  protoplas- 

*  According  to  Calvert  (Jour,  prakt.  Chem.,  1869,  p.  122),  cotton  samples 
from  different  countries  contain  the  following  percentages  of  phosphoric  acid 
soluble  in  water: 

Egypt 0.055  Surat 0.027 

New  Orleans 0.049  Carthagena. .  .  0.035  to  0.050 

Bengal 0.055  Cyprus 0.050 

t  It  is  sometimes  found  that  mercerized  Egyptian  cotton  contains  a  larger 
percentage  of  iron  than  is  naturally  present  in  the  untreated  fibre.  This  is 
doubtless  caused  by  the  presence  of  iron  in  the  caustic  soda  solution  employed 
for  the  mercerization;  sodium  ferrate,  in  fact,  appears  to  be  a  normal  constituent 


CHEMICAL  PROPERTIES   OF  COTTON;    CELLULOSE     267 


mic  residue.*  Different  varieties  of  cotton,  on  analysis,  show 
the  following  percentages  of  nitrogen;!  some  of  this,  however, 
may  be  derived  from  mineral  nitrates  which  may  be  present  in 
slight  amount  in  the  fibre  (Bowman):  t 

Per  Cent  Nitrogen. 

American o .  30 

Sea-island o .  34 

Bengal o .  39 

Rough  Peruvian o .  33 

Egyptian  (white) o .  29 

' '         (brown) 0.42 

Mean x- o •  345          « 

it 

of  such  solutions,  being  derived  from  the  solvent  action  of  caustic  soda  on  the 
iron  rust  present  in  the  tanks.  Lefevre  (Rev.  Gen.  Mat.  Col.,  1909,  p.  281)  gives 
the  following  analyses  of  samples  of  mercerized  Egyptian  cotton: 


Kind  of  Cotton. 

Ash,  Per  Cent. 

Oxide  of  Iron  in 
Ash,  Per  Cent. 

Color  of  Ash. 

Natural  Egyptian 

o  624. 

I    ?O 

White 

Mercerized  Egyptian  

0.137 

8.02 

Greenish 

Gray  mercerized  Egyptian  

0.403 

2.31 

Yellow  gray 

Bleached  mercerized  Egyptian  . 

0.088 

5-45 

Greenish 

*  The  amount  of  nitrogenous  matter  present  in  cotton  may  be  determined 
by  KjehldahPs  process,  as  follows:  5  grams  of  cotton  material  is  chopped  up 
and  heated  in  a  flask  with  30  c.c.  of  concentrated  sulphuric  acid  and  2  grams 
of  potassium  permanganate.  This  treatment  results  in  a  complete  decomposi- 
tion of  the  nitrogenous  matter  with  the  liberation  of  ammonia,  which  immediately 
combines  with  the  sulphuric  acid  present  to  form  ammonium  sulphate.  An  excess 
of  caustic  soda  solution  is  now  carefully  added,  and  the  solution  boiled.  This 
results  in  the  liberation  of  free  ammonia  as  a  gas.  The  latter  is  passed  into  a 
definite  volume  of  TV  normal  sulphuric  acid  solution,  and  the  excess  of  acid  not 
neutralized  by  the  ammonia  is  subsequently  titrated  with  yV  normal  caustic  soda 
solution,  using  methyl  orange  as  an  indicator.  The  amount  of  sulphuric  acid 
neutralized  measures  the  quantity  of  ammonia  formed,  which  in  turn  determines 
the  amount  of  nitrogen  present  in  the  original  cotton.  The  quantity  of  nitrogen 
so  obtained  multiplied  by  the  factor  6.4  gives  the  amount  of  nitrogenous  matter 
present  as  an  albuminoid. 

f  According  to  analyses  by  Schindler  (Jour.  Soc.  Dyers'  6*  Col.,  1908,  p.  106) 
raw  Egyptian  cotton  gave  2.50  per  cent  of  nitrogen.  By  boiling  the  cotton 
for  8  hours  with  caustic  soda  solution  the  amount  of  nitrogen  was  reduced  to 
0.064  P61"  cent. 

J  It  is  likely  that  in  the  process  of  bleaching  most  of   the  albuminous  matter 


268  THE  TEXTILE  FIBRES 

3.  Cellulose. — This  is  one  of  the  most  important  of  the 
naturally  occurring  chemical  compounds,  as  it  forms  the  basis 
of  all  vegetable  tissue.  Chemically  it  consists  of  carbon,  hydro- 
gen, and  oxygen,  and  has  the  empirical  formula  CoHioOs.* 
It  belongs  to  a  class  of  bodies  known  as  carbohydrates,  and  is 
closely  related  to  the  starches,  f  dextrins,  and  sugars.  Chemically 
considered,  these  compounds  must  all  be  regarded  as  alcohols 
containing  aldehydic  and  ketonic  groups.  The  word  "  cellulose  " 
must  not  be  taken  as  signifying  a  simple  definite  substance  of 
unvarying  properties,  but  rather  as  a  generic  term  including 
quite  a  number  of  bodies  of  similar  chemical  nature.  Like 
starch  and  other  complex  carbohydrates  of  organic  physical 
structure,  cellulose  will  vary  somewhat  in  its  properties,  depend- 
ing upon  its  source  or  derivation.  As  a  class  the  celluloses 
exhibit  certain  chemical  characteristics,  by  means  of  which 
they  may  be  distinguished  from  associated  bodies  of  allied 
chemical  constitution.  Physically  they  are  colorless  amorphous 
substances  capable  of  withstanding  rather  high  temperatures 
without  decomposition.  They  are  insoluble  in  nearly  all  of 
the  usual  solvents, %  such  as  water,  alcohol,  ether,  etc.,  but 
dissolve  more  or  less  completely  in  an  ammoniacal  solution  of 

is  removed  from  the  cotton  fibre.  Haller  has  shown  that  bleached  cotton  is  not 
tinted  so  deeply  as  raw  cotton  with  an  acid  solution  of  safranin,  and  he  con- 
cludes that  this  is  due  to  the  albuminous  matter  acting  as  a  mordant  for  the 
dyestuff. 

*The  cellulose  of  all  vegetable  tissues,  even  in  a  highly  purified  condition, 
appears  to  contain  a  small  amount  of  mineral  constituents,  apparently  forming 
an  integral  or  organic  portion  of  the  fibre  structure.  The  amount  of  ash,  for 
instance,  obtained  from  bleached  cotton  is  about  o.i  to  0.4  per  cent.  Even 
"Swedish"  filter-paper,  which  has  been  treated  with  hydrochloric  and  hydrofluoric 
acids  for  the  removal  of  inorganic  constituents,  will  still  contain  from  0.03  to 
0.05  per  cent  of  ash. 

f  Though  cellulose  appears  to  be  somewhat  analogous  to  these  bodies,  it  never- 
theless differs  from  them  in  its  much  greater  resistance  to  the  hydrolytic  action 
of  acids,  alkalies,  and  enzymes.  The  latter  reagents  readily  split  up  the  starches 
into  simpler  bodies;  but  no  such  reaction,  through  artificial  means  at  least,  has 
been  observed  in  the  case  of  cellulose.  That  such  a  reaction,  however,  takes 
place  in  the  tissues  of  the  growing  plant  there  is  no  doubt. 

J  Deming  (Jour.  Amer.  Chew.  Soc.,  1911,  p.  1515)  states  that  cellulose  (in  the 
form  of  filter-paper)  is  soluble  in  concentrated  aqueous  solutions  of  antimony 
trichloride,  stannous  chloride,  and  zinc  bromide. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     269 

copper  oxide  (Schweitzer's  reagent)*  and  in  solutions  of  zinc 
chloride  and  phosphoric  acid.  Solution  in  these  reagents 
apparently  takes  place  without  decomposition,  f  as  the  cellulose 
may  be  precipitated  unchanged  J  therefrom  by  the  addition  of 
acids  and  various  salts,  the  precipitate  being  known  as  "  regen- 
erated "  cellulose. 

In  order  to  obtain  pure  cellulose  for  chemical  purposes 
it  is  customary  to  treat  cotton  successively  with  dilute  caustic 
alkali,  dilute  acid,  water,  alcohol,  and  ether.  Cross  and  Bevan 

*  Cross  and  Bevan  make  the  following  remarks  respecting  this  reagent:  The 
solutions  of  cuprammonium  compounds  generally,  in  the  presence  of  excess 
of  ammonia,  attack  cellulose  rapidly  in  the  cold,  forming  a  series  of  gelatinous 
hydrates,  passing  ultimately  into  fully  soluble  forms.  The  solutions  of  the  pure 
cuprammonium  hydroxide  are  more  active  in  producing  these  effects  than  the 
solutions  resulting  from  the  decomposition  of  a  copper  salt  with  excess  of  ammonia. 
Two  methods  are  in  common  use  for  the  preparation  of  these  solutions,  which 
should  contain  10  to  15  per  cent  of  ammonia  and  2  to  2.5  per  cent  of  copper 
as  the  oxide,  (i)  Hydrated  copper  oxide  is  prepared  by  precipitating  a  solu- 
tion of  copper  sulphate  of  2  per  cent  strength  with  a  slight  excess  of  a  dilute  solu- 
tion of  sodium  hydrate.  The  precipitate  is  washed  until  it  is  entirely  free  from 
alkali.  The  original  solution  in  which  the  solution  takes  place,  as  well  as  the 
water  used  in  washing,  should  contain  a  small  quantity  of  glycerol.  The  washed 
precipitate  is  well  drained,  and  then  mixed  with  a  quantity  of  a  10  per  cent  solu- 
tion of  glycerol,  in  contact  with  which  it  may  be  preserved  unchanged  in  stoppered 
bottles.  When  desired  for  use,  the  oxide  is  washed  free  from  glycerol  and  dis- 
solved in  ammonia  water  (of  15  to  20  per  cent  strength).  (2)  Metallic  copper, 
in  the  form  of  sheet  or  turnings,  is  placed  in  a  cylinder  and  covered  with  strong 
ammonia;  atmospheric  air  is  caused  to  bubble  through  the  column  of  liquid 
at  a  rate  calculated  to  40  times  the  volume  of  the  liquid  used  per  hour.  In 
about  six  hours  a  liquid  of  the  requisite  composition  is  obtained.  Solutions  con- 
taining 5  to  10  per  cent  of  cellulose  are  readily  prepared  by  digestion  in  the  cold 
with  10  to  20  times  the  weight  of  cuprammonium  solution,  a  rather  ropy  or 
gelatinous  solution  being  obtained.  The  cellulose  is  readily  precipitated  from  the 
solution:  (a)  By  the  addition  of  neutral  dehydrating  agents,  such  as  alcohol, 
sodium  chloride,  and  other  salts  of  the  alkalies,  and  (6)  by  the  addition  of  acids, 
in  which  case  the  cellulose  is  precipitated  in  the  pure  state,  or  free  from  copper 
oxide. 

f  Cross  and  Bevan  attribute  the  solution  of  cellulose  in  cuprammonium  to 
the  preliminary  formation  of  a  soluble  gelatinous  hydrate  induced  by  the  presence 
of  the  copper. 

J  That  the  alteration  in  the  cellulose  is  merely  structural  has  been  disputed, 
by  reason  of  the  fact  that  filaments  prepared  from  the  precipitated  cellulose 
have  a  greatly  increased  affinity  for  dyestuffs;  they  appear  to  act  more  as  a 
hydrocellulose. 


270  THE  TEXTILE  FIBRES 

recommend  the  following  procedure  in  the  isolation  of  pure 
cellulose  in  the  study  of  the  vegetable  fibres:  (a)  The  fibrous 
raw  material  is  boiled  with  a  dilute  (i  to  2  per  cent)  solution 
of  caustic  soda,  and,  after  thorough  washing,  is  (b)  exposed  in 
the  moist  state  to  an  atmosphere  of  chlorin  gas;  (c)  it  is 
again  treated  with  boiling  alkali.  By  such  treatment  the  "  non- 
cellulose  "  constituents  of  most  vegetable  fibres  are  removed, 
and  a  residue  of  pure  cellulose  is  obtained.  A  subsequent 
slight  treatment  with  a  dilute  solution  of  chloride  of  lime  for 
the  removal  of  traces  of  coloring  matters,  and  a  final  washing 
with  alcohol  and  ether  completes  the  purification.* 

The  result  of  this  treatment  is  to  remove  all  foreign  and 
encrusting  materials  from  the  raw  fibre,  and  possibly  also  to 
remove  the  thin,  external  cuticular  membrane  which  may  be 
chemically  different  from  the  rest  of  the  tissue.  The  specific 

*  Beltzer  describes  the  following  method  for  the  preparation  of  normal  pure 
cellulose  from  cotton:  (a)  The  cotton  is  first  carefully  combed  in  order  to  remove 
mechanically  all  dirt  and  foreign  matter;  (b)  it  is  then  boiled  for  six  to  eight  hours 
in  a  solution  of  caustic  soda  of  2^°  Tw.  The  liquor  is  then  squeezed  out  and  the 
cotton  rinsed  until  the  wash- water  is  no  longer  colored;  (c)  the  cotton  is  next 
treated  with  a  solution  of  hydrochloric  acid  of  2°  Tw.  and  at  120°  F.  for  3-4 
hours;  then  washed  in  warm  water;  (d)  the  fibre  is  then  bleached  in  a  solution 
of  sodium  hypochlorite  at  2°  Tw.  at  a  temperature  of  80°  F.  for  6-8  hours, 
after  which  it  is  rinsed  in  lukewarm  water  and  squeezed;  (e)  a  second  treatment 
with  acid  is  then  given  similar  to  the  first,  and  the  cotton  is  again  well  rinsed; 
(/)  the  cotton  is  finally  treated  with  a  solution  of  sodium  bisulphite  of  2°  Tw. 
at  120°  F.  for  five  hours,  then  well  rinsed  in  lukewarm  distilled  water.  The  cotton 
is  then  squeezed  and  dried  at  a  moderate  temperature.  The  analysis  of  this 
dried  cellulose  should  correspond  to  C6Hi0O5,  and  the  ash  on  ignition  should  not 
exceed  0.05  per  cent.  This  cellulose  should  not  contain  either  hydrocellulose 
or  oxycellulose,  the  presence  of  which  may  be  detected  by  sensitive  qualitative 
tests.  This  normal  pure  cellulose  should  be  very  resistant  to  the  action  of  caustic 
alkalies;  after  prolonged  treatment  with  boiling  dilute  caustic  soda  solution, 
followed  by  washing,  acidulation,  and  rinsing  the  weight  of  the  cellulose  should 
remain  constant.  Any  loss  will  indicate  partial  solution  due  to  presence  of  hydro- 
cellulose  or  oxycellulose,  both  of  which  are  soluble  in  caustic  soda.  To  remove 
these  impurities  the  cotton  should  be  again  boiled  with  a  solution  of  caustic  soda 
of  2°  Tw.,  rinsed  in  distilled  water,  acidulated  at  120°  F.,  with  a  solution  of 
hydrofluoric  acid  of  i^°  Tw.,  washed,  treated  with  bisulphite,  finally  thoroughly 
rinsed,  squeezed,  and  dried  again.  On  distillation  with  hydrochloric  acid  this 
purified  cellulose  should  not  give  any  furfural,  nor  give  a  rose  color  with  phloro- 
glucinol-hydrochloric  acid  reagent,  and  its  copper  index  with  Fehling's  solution 
should  be  zero  or  nearly  so. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     271 

gravity  or  density  of  cellulose  as  obtained  in  the  usual  manner 
is  about  1.5,  and  this  also  represents  the  density  of  cotton  and 
most  other  plant  fibres.  Chemically  considered,  cellulose  is  a 
derivative  of  the  open-chain  or  paraffin  series  of  hydrocarbons, 
and  furthermore  it  exhibits  the  reactions  of  a  saturated  com- 
pound. As  with  the  other  carbohydrates,  chemists  have  found 
it  a  matter  of  great  difficulty  to  ascertain  even  approximately 
the  true  molecular  formula  of  cellulose.  Though  its  empirical 
formula  is  CeHioOs,  this  in  no  way  represents  the  true  molecular 
complexity  of  the  substance.  From  a  study,  however,  of  its 
various  synthetical  derivatives,  with  special  reference  to  its 
esters,  such  as  the  acetates,  benzoates,  and  nitrates,  the  pro- 
visional formula  of  Ci2H2oOio  has  been  given  to  the  cellulose 
molecule.*  The  nature  and  position  of  the  various  organic 
groups  present  in  this  molecular  formula,  however,  have  yet 
to  be  explained. 

There  has  been  a  considerable  amount  of  speculation  among 
chemists  as  to  the  chemical  nature  and  constitution  of  cellulose, 
but  there  has  been  so  little  experimental  data  on  which  to 
frame  an  intelligent  theory,  that  most  of  these  speculations  are 
mere  scientific  guesswork,  and  have  little  more  than  a  pro- 
visional value.  From  the  action  of  zinc  chloride  on  cellulose 
it  has  been  presumed  that  the  cellulose  molecule  contains 
hydroxyl  groups  of  such  a  nature  as  to  give  it  a  salt-like  property, 
and  the  solution  of  the  cellulose  in  the  zinc  chloride  is  supposed 
to  be  due  to  the  formation  of  a  kind  of  double  salt.  There  also 
appears  to  be  a  chemical  reaction  of  limited  degree  between 
cellulose  and  dilute  solutions  of  caustic  alkalies  and  mineral 
acids.  According  to  Mills,  the  relative  molecular  ratio  of  the 
absorption  by  cellulose  of  alkalies  and  acids  is  represented  by 
ioNaOH:3HCl.  From  this  and  other  considerations,  it  would 
appear  that  cellulose  exhibits  the  properties  of  a  feeble  acid 
and  of  a  still  more  feeble  base. 

*  The  fact  that  cellulose  can  exist  in  the  colloidal  condition,  and  is  difficultly 
soluble  is  not  considered  as  indicating,  as  previously  supposed,  a  high  molecular 
weight,  for  both  alumina  and  silicic  acid  exist  in  the  colloidal  state  and  it  is  not 
necessary  to  assume  a  high  molecular  weight  for  these  bodies. 


272  THE  TEXTILE  FIBRES 

Vignon  has  proposed  to  give  cellulose  the  following  con- 
stitutional formula: 

O CHV 

!    \ 

O        >(CHOH)3. 

I      / 
CH2— CH7 

This  is  based  on  a  study  of  the  highest  nitrate  of  cellulose 
and  the  decomposition  of  the  nitrate  by  alkalies  with  formation 
of  hydroxypyruvic  acid.  The  structure  given,  however,  is 
more  or  less  hypothetical  in  nature,  and  needs  experimental 
confirmation  in  many  particulars  before  it  can  be  accepted 
without  question.  The  older  chemical  configuration  of  cellulose 
given  by  Bowman, 

H  H    H 

L  _  _     '   ' 

Jl  \^s  \-s \-s \~s  \^  V^  -"•» 

I   I         I    I 

OH  OH       OH  OH  OH 

is  without  any  experimental  reason  for  its  existence,  and  the 
idea  that  it  contains  an  unsaturated  carbon  grouping,  — C=C — , 
has  been  proved  erroneous.  From  a  study  of  the  osazones 
of  oxy cellulose,  Vignon  has  ascribed  to  this  latter  body  a 
constitutional  formula  having  the  group, 

/COH 

(CHOH)8< 

XCH— CO, 

\/ 
O 

.  -    % 

in  union  with  varying  proportions  of  residual  cellulose. 

The  existence  of  a  compound  containing  cellulose  and  sul- 
phuric acid  in  the  proportion  4CeHioOo  :  H2SO4  is  put  forward 
as  a  proof  that  in  its  reactions  cellulose  behaves  like  a  complex 
molecule  of  at  least  24  carbon  atoms.* 

*  See  Cross,  Bevan,  and  Briggs,  Berichie,  1905,  p.  1859. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     273 


Green,*  however,  believes  the  simple  formula  CeHioOs  as 
amply  justified,  f  He  considers  the  adoption  of  Ci2H2oOio 
as  the  proper  formula,  based  on  the  existence  of  tri-  and  penta- 
nitrates,  as  erroneous,  and  considers  the  existence  of  such  nitrates 
as  very  doubtful.  He  proposes  the  following  constitutional 
formula  for  cellulose: 

CH(OH)—  CH—  CH—  OH 


i 
CH(OH)— CH— CH2 

and  claims  that  such  a  formula  exhibits  the  aldehydic  nature  of 
cellulose  as  follows: 

-CH— OH 
-CH2 

which  by  fixation  of  water  becomes: 

-CH(OH)2 

-CH2(OH) 

and  then: 

-CHO 

-CH2(OH) 

This  formula  is  also  in  accord  with  the  formation  of  trinitro 
and  triacetyl  derivatives  as  the  limits  of  esterification  of  cel- 
lulose, for  higher  derivatives  could  only  be  obtained  by  the 
transformation  of  the  two  central  oxygen  atoms  into  two 
hydroxyl  groups.  It  also  explains  why  cellulose  does  not  react 
with  either  phenylhydrazine  or  hydroxylamine,  as  it  does  not 
contain  carbonyl  (CO)  groups,  either  ketonic  or  aldehydic; 

*  Zeit.  Farb.  u.  Text.  Ind.,  1904,  p.  97. 

t  Recent  work  in  the  constitution  of  cellulose  indicates  that  the  generally 
accepted  formula  for  starch,  cellulose,  etc.  (CeHioOs)^,  is  incorrect,  and  should  be 
replaced  by  (C6HioO5)«-H2O.  (See  H.  Kiliani,  Chem.  Zeit.,  1908,  p.  366.) 


274  THE  TEXTILE  FIBRES 

while,  on  the  other  hand,  by  simple  hydrolysis  it  yields  derivatives 
containing  the  carbonyl  group.  Green  considers  the  existence 
of  a  tetracetate  of  cellulose  as  doubtful,  but  even  if  such  does 
exist,  its  formation  is  probably  due  to  a  hydrolysis  which 
precedes  the  acetylization.  According  to  Fenton,  when  cel- 
lulose is  treated  with  dry  hydrochloric  acid  gas  without  heat- 
ing, there  is  formed  chlormethyl-furfural : 

CH=C— CHO 
CH^-C— CH2— Cl. 

Green  claims  that  his  formula  explains  this  remarkable 
reaction.*  By  hydration  there  is  first  formed  the  intermediate 
compound : 

CH=C— CH(OH) 

[==€    CH2 


*  Green  says  that  a  successful  formula  for  cellulose  must  explain  the  following 
facts:  (i)  A  trinitrated  derivative;  (2)  a  triacetyl  derivative;  (3)  with  concentrated 
caustic  soda  cellulose  gives  a  compound  which  is  decomposed  by  water  to  form 
cellulose  hydrate  (mercerizing),  which  is  much  more  soluble  than  cellulose  itself 
in  solutions  of  ammoniacal  copper  oxide  and  zinc  chlorides;  (4)  treated  with 
carbon  disulphide  the  alkali  cellulose  is  converted  into  cellulose  thiocarbonate 
(viscose),  which  is  easily  soluble  in  water;  (5)  cellulose  does  not  react  with  phenyl- 
hydrazine  or  hydroxylamine;  (6)  as  an  ultimate  product  of  hydrolysis  (with 
sulphuric  acid)  cellulose  gives  glucose;  (7)  Fenton's  reaction  or  the  formation  of 
chlormethylfurfural;  (8)  the  formation  of  oxycellulose  by  the  oxidation  of  cellu- 
lose; this  body  has  properties  very  similar  to  cellulose  itself,  but  has  a  decided 
acid  character,  and  when  distilled  with  dilute  sulphuric  acid  it  gives  furfural; 
(9)  when  oxycellulose  is  boiled  with  milk-of-lime  it  gives  dioxybutyric  acid  and 
iso-glucosic  acid  (Faber  and  Follens) : 

CH(OH) — CH— CO-OH 


CH(OH)-     CH— CO-OH 

(10)  nitrocelluloses,  when  treated  with  dilute  caustic  soda,  give  oxypyruvic  acid 
(Will):  CH2(OH)-CO-CO-OH. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     275 
which  gives  by  addition  of  hydrochloric  acid: 

CH=C—  CH(OH)2 

> 

=C—  CH2-C1 


and  by  elimination  of  water: 

CH--C—  CHO 

> 

CH=C—  CH2-C1 

The  intermediate  product  assumed  by  Green  in  the  Fenton 
reaction,  appears  to  have  the  same  empirical  formula  as  lignin, 
CeHeOs,  a  substance  associated  with  cellulose  in  woody  fibre. 
This  would  seem  to  furnish  a  physiological  explanation  of  the 
relation  which  exists  between  lignin  and  cellulose.  The  color 
reactions  observed  by  Fenton  with  his  new  derivatives  would 
also  seem  to  demonstrate  this. 

Regarded  from  the  point  of  view  of  the  ionic  theory,  cellulose 
is  considered  as  a  molecular  aggregate  consisting  of  a  mixture 
of  ions  of  varying  dimensions.  Hence,  cellulose  as  a  typical 
colloid  has  no  definite  reactive  unit  as  a  body  which  takes  the 
crystalline  form,  nor  a  fixed  molecular  constitution  which  may 
be  represented  in  the  limits  of  a  constitutional  formula;  for  the 
cellulose  molecule  cannot  be  regarded  as  a  static  unit,  but 
rather  as  a  dynamic  equilibrium;  its  reacting  unit  at  any  time 
being  a  function  of  the  conditions  surrounding  it.  This  view 
of  the  constitution  of  cellulose  has  been  advanced  by  C.  F. 
Cross. 

In  its  chemical  reactions  cellulose  is  particularly  inert,  com- 
bining with  only  a  few  substances,  and  then  only  with  great 
difficulty  and  under  peculiar  conditions.  It  is  quite  resistant 
to  the  processes  of  oxidation  and  reduction,  and  hydrolysis  and 
dehydration.  This  high  degree  of  resistance  to  hydrolysis 
(alkaline)  and  oxidation  belongs  only  to  cotton  cellulose  and  to 


276  THE  TEXTILE  FIBRES 

the  group  of  which  it  is  the  type,  and  which  includes  the  cellu- 
lose of  flax,  ramie,  and  hemp.  A  large  number  of  celluloses, 
on  the  other  hand,  are  distinguished  by  considerable  reactivity, 
due  to  the  presence  of  "  free  "  carbonyl  groups,  and  are  there- 
fore more  or  less  easily  hydrolyzed  and  oxidized.  The  celluloses 
of  the  cereal  straws  and  esparto  grass  are  of  this  type,  hence 
the  relative  inferiority  of  the  papers  into  the  composition  of 
which  they  enter.*  Cotton  cellulose  is  also  distinguished  by 
the  fact  that  it  gives  no  furfural  when  distilled  with  acid,  and 
by  being  precipitated  unchanged  from  its  solution  in  alkaline 
carbon  disulphide.  Concentrated  sulphuric  acid  dissolves 
cellulose  with  the  production  of  a  viscous  solution;  dilution 
with  water  causes  the  precipitation  of  an  amorphous  substance 
known  as  amyloid,  a  starch-like  body  having  the  formula 
Ci2H22On,  and  like  starch  it  is  colored  blue  with  iodin.  On 
this  reaction  is  based  the  method  of  testing  for  cellulose,  by 
applying  sulphuric  acid  and  iodin.  On  boiling  with  dilute 
sulphuric  acid,  cellulose  is  converted  into  dextrin  and  glucose. 
On  heating  with  acetic  anhydride  to  180°  C.,  cellulose  is  con- 
verted into  an  acetyl  derivative  having  the  formula 
Ci2Hi4O4(OCOCH3)6.  Cellulose  does  not  react  directly  with 
acetic  anhydride,  but  at  the  temperature  above  given  and  with 
six  times  its  weight  of  the  anhydride  it  gives  the  derivative 
having  the  above  formula,  and  which  may  be  called  the  triacetate. 
With  a  smaller  quantity  of  acetic  anhydride,  a  mixture  of  lower 
acetates  is  obtained  which  are  insoluble  in  glacial  acetic  acid. 
The  triacetate  is  readily  soluble  in  this  acid,  however,  and  also 
in  nitrobenzene.  Its  solutions  are  very  viscous.  Regenerated 
cellulose,  prepared  by  precipitation  of  viscous  solutions,  reacts 
with  acetic  anhydride  directly,  and  gives  what  appears  to  be 
the  tetracetate.f  By  the  moderated  action  of  concentrated 
acids  and  various  acid  salts,  cellulose  appears  to  undergo  a 
process  of  hydrolysis,  being  converted  into  a  friable  amorphous 
body  known  as  hydrocellulose.  This  reaction  is  of  importance 

*  Cross  and  Be  van,  Jour.  Chem.  Soc.,  1894,  p.  472. 

f  For  further  remarks  concerning  the  acetylation  of  cellulose  see  Cross  and 
Bevan,  Cellulose  and  Researches  on  Cellulose. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     277 

in  the  carbonizing  process  for  removing  vegetable  matter  from 
woolen  goods. 

In  the  carbonizing  process  the  material  to  be  treated  is 
impregnated  with  a  boiling  solution  of  sulphuric  acid  of  2°  Be., 
squeezed,  dried,  and  then  beaten  or  washed  thoroughly  to  remove 
the  disintegrated  cotton  fibres.  In  another  method  gaseous 
hydrochloric  acid  is  allowed  to  act  on  the  material  in  place  of 
the  sulphuric  acid  solution.  Solutions  of  certain  acidic  salts 
such  as  magnesium  chloride  and  aluminium  chloride  are  also 
employed  for  carbonizing.  These  salts  when  dried  into  the 
fibre  liberate  free  hydrochloric  acid  which  decomposes  the 
vegetable  matter.  With  magnesium  chloride  it  is  customary 
to  use  a  solution  of  9°  Be.,  and  with  aluminium  chloride  one 
of  7°  Be.  the  material  being  saturated  with  one  of  these  solu- 
tions and  dried  at  a  temperature  of  about  300°  F.  After  this 
the  material  is  well  washed.  The  choice  of  the  carbonizing 
agent  will  largely  depend  on  the  character  of  the  goods  to  be 
treated  and  the  nature  of  the  dyestuff  with  which  they  may 
be  colored. 

Hydrocellulose  is  also  manufactured  for  the  purpose  of  mak- 
ing guncotton,  being  used  in  place  of  cotton;  for  when  treated 
with  the  necessary  acid  mixture  it  furnishes  a  more  sensitive 
guncotton  which  explodes  more  rapidly  and  therefore  is  better 
adapted  for  the  making  of  detonating  fuses. 

A  concentrated  solution  of  zinc  chloride  will  dissolve  cellulose 
on  heating  and  digesting  for  some  time.*  This  solution  has 

*  Cross  and  Bevan  recommend  the  following  method  for  preparing  this  solu- 
tion of  cellulose:  4  to  6  parts  of  anhydrous  zinc  chloride  are  dissolved  in  6  to  10 
parts  of  water,  and  i  part  of  bleached  cotton  is  then  stirred  in  until  evenly 
moistened.  The  mixture  is  digested  for  a  time  at  6o°.to  80°  C.,  when  the  cellulose 
is  gelatinized;  the  solution  is  completed  by  heating  on  a  water-bath  and  stirring 
from  time  to  time,  and  replacing  the  water  which  evaporates.  In  this  manner 
a  homogeneous  syrup  is  obtained.  This  solution  of  cellulose  is  entirely  decom- 
posed by  dilution,  the  cellulose  being  precipitated  as  a  hydrate  in  combination 
with  zinc  oxide.  On  washing  this  precipitate  with  hydrochloric  acid  a  pure 
cellulose  hydrate  is  obtained,  the  quantity  recovered  being  approximately  equal 
to  the  original  cellulose  taken.  When  precipitated  by  the  addition  of  alcohol, 
a  compound  of  cellulose  and  zinc  oxide  is  obtained,  with  18  to  25  per  cent  of 
ZnO,  and  having  the  approximate  molecular  ratio  of  2CeHi0O5  :  ZnO. 


278  THE  TEXTILE   FIBRES 

been  employed  industrially  for  the  preparation  of  cellulose 
filaments,  which  are  subsequently  treated  with  hydrochloric 
acid  and  washed  for  the  purpose  of  removing  the  zinc  salt;  the 
thread  is  then  carbonized  and  is  employed  for  the  carbon 
filament  of  incandescent  electric  lamps.*  A  concentrated  solu- 
tion of  zinc  chloride  in  hydrochloric  acid  dissolves  cellulose 
quite  rapidly  and  in  the  cold.f  This  latter  method  is  useful 
in  the  laboratory  for  the  study  of  celluloses,  but  as  yet  has 
received  no  technical  application.  By  means  of  this  solution 
it  has  been  shown  that  the  cellulose  molecule  does  not  contain 
any  unsaturated  carbon  groups,  for  it  exhibits  no  absorption 
of  bromin.  A  solution  of  a  lignocellulose,  on  the  other  hand, 
gives  a  marked  bromin  absorption,  thus  showing  evidence  of 
unsaturated  carbon  groups. 

Cellulose  is  colored  a  deep  violet  by  a  solution  of  zinc  chlor- 
iodide,  and  this  reagent  is  employed  as  a  delicate  test  for  the 
presence  of  cellulose.  The  reagent  may  be  best  prepared  by 
using  90  parts  of  a  concentrated  solution  of  zinc  chloride,  add- 
ing 6  parts  of  potassium  iodide  in  10  parts  of  water,  and  iodin 
until  saturated. 

When  cellulose  is  treated  with  concentrated  caustic  alkalies, 
it  undergoes  a  change  which  may  be  crudely  referred  to  as 
"  mercerization,"  whereby  a  compound  known  as  alkali-cellulose 
is  formed,  in  which  the  molecular  ratio  of  alkali  to  cellulose  may 
be  given  as  Ci2H2oOio:  NaOH.  When  this  body  is  treated 
with  carbon  disulphide,  a  substance  known  as  cellulose  thiocar- 
bonate  or  xanthate  is  formed.  This  body  yields  a  very  viscous 


*  The  threads  for  the  production  of  the  carbon  filaments  are  prepared  by 
forcing  the  syrupy  solution  of  cellulose  through  fine  glass  orifices  into  alcohol, 
whereby  the  cellulose  is  precipitated  in  a  continuous  thread.  The  filaments 
obtained  from  this  source  are  more  homogeneous  in  composition  and  possess 
greater  elasticity  and  a  more  uniform  electrical  resistance  than  filaments  of  any 
other  origin. 

f  The  reagent  is  prepared  by  dissolving  one  part  of  zinc  chloride  in  twice  its 
weight  of  concentrated  hydrochloric  acid.  If  the  solution  of  cellulose  obtained 
with  this  solvent  is  diluted  when  fresh,  the  cellulose  will  be  precipitated  unaltered; 
but  if  the  solution  is  allowed  to  stand,  the  cellulose  is  rapidly  resolved  into 
decomposition  products,  such  as  dextrin,  etc.,  which  are  entirely  soluble  in  water. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     279 

solution  with  water  and  has  been  utilized  for  various  technica1 
purposes  under  the  name  of  viscose.* 

For  the  preparation  of  viscose  it  is  best  to  employ  the 
following  molecular  proportions  of  the  reagents: 

CeHioOs:  2NaOH:  CS2  (with  30  to  40  H2O). 

The  reaction  is  carried  out  in  practice  by  treating  bleached 
cotton  (though  other  forms  of  cellulose,  such  as  purified  wood- 
pulp,  may  also  be  used)  with  excess  of  a  15  per  cent  solution 
of  caustic  soda,  then  squeezing  out  the  excess  of  liquor,  but 
leaving  in  the  fibre  about  three  times  its  weight  of  the  solution. 
The  mass  is  then  mixed  with  about  50  per  cent  (on  the  weight 
of  the  cotton)  of  carbon  disulphide,  and  allowed  to  stand  in  a 
covered  vessel  for  about  three  hours  at  the  ordinary  temperature; 
after  which  sufficient  water  is  added  to  cover  the  mass,  and  the 
hydration  allowed  to  proceed  for  several  hours  longer.  The 
mass  is  then  stirred  up  and  a  homogeneous  solution  is  obtained 
which  may  be  diluted  to  any  desired  degree.  The  solution 
thus  prepared  has  a  yellow  color,  which,  however,  is  due  to  the 
presence  of  various  thiocarbonates  which  occur  as  by-products  in 
the  reaction.  By  treating  the  solution  with  a  saturated  solu- 
tion of  common  salt  or  with  alcohol,  pure  cellulose  thiocar- 
bonate  is  precipitated  as  greenish  white  flocculent  mass,  which 
may  be  redissolved  in  water,  giving  a  colorless  or  faintly  yellow- 
colored  solution.  On  the  addition  of  various  metallic  salts 
to  this  solution,  the  corresponding  xanthates  may  be  precipitated. 
With  iodin  a  precipitate  of  dioxy-thiocarbonate  is  formed,  which 
may  be  said  to  take  place  in  accordance  with  the  following 
equation  (X  representing  the  residue  of  the  cellulose  molecule)  : 


Cellulose   xanthate   undergoes   spontaneous   decomposition, 
splitting  up  into  cellulose  hydrate,  alkali,  and  carbon  disulphide; 

*  See  Viscose,  Chapter  XIV. 


280  THE  TEXTILE  FIBRES 

this  cellulose  hydrate  is  also  known  as  regenerated  cellulose. 
When  this  decomposition  takes  place  in  solutions  containing 
more  than  i  per  cent  of  cellulose,  a  firm  jelly  of  coagulated 
cellulose  is  produced  of  the  same  volume  as  the  original  solu- 
tion. A  solution  containing  as  much  as  10  per  cent  of  cellulose 
decomposes  to  a  substantial  solid  of  hydrated  cellulose  which 
gives  up  its  water  with  extreme  slowness.  The  cellulose 
regenerated  in  this  manner  is  probably  in  the  "  colloidal  " 
form.  This  substance  can  also  be  precipitated  from  the  xan- 
thate  solution  by  the  addition  of  various  salts,  such  as  ammonium 
chloride. 

Alkali  cellulose  also  reacts  with  benzoyl  chloride,  with  the 
formation  of  cellulose  benzoate.*  Another  ester  of  cellulose 
is  the  acetate,  which  can  be  made  by  the  action  of  acetic  anhy- 
dride on  cellulose  f  heated  in  a  sealed  tubej — regenerated  cel- 
lulose can  also  be  employed.  By  varying  the  conditions  of 
treatment  a  number  of  different  acetates  have  been  prepared.  § 

*  See  Cross  and  Bevan,  Cellulose,  p.  32,  and  Researches  on  Cellulose,  p.  34,  etc. 

f  Cross  (Jour.  Soc.  Chem.  Ind.,  1904,  p.  297)  states  that  80  to  90  per  cent 
of  acetyl  groups  may  be  introduced  into  the  cellulose  molecule  without  apparently 
changing  the  original  properties  of  the  cellulose. 

t  According  to  a  recent  patent  (Eng.  Pat.  1905,  No.  9998),  an  almost  theoret- 
ical yield  of  cellulose  acetate  may  be  obtained  by  conducting  the  acetylation  in 
the  presence  of  methyl  sulphate;  the  process  given  being  as  follows:  30  parts  of 
cotton  are  treated  in  a  bath  with  70  parts  of  acetic  anhydride,  120  parts  of  glacial 
acetic  acid,  and  3  parts  of  dimethyl  sulphate  until  solution  is  almost  complete. 
The  solution  is  then  filtered  and  the  filtrate  is  poured  into  a  large  quantity  of 
water,  whereupon  the  acetate  of  cellulose  is  precipitated. 

§  The  acetate  of  cellulose  may  be  prepared  by  heating  a  mixture  of  hydro- 
cellulose,  acetic  anhydride,  and  sulphuric  acid  to  6o°-7o°  C.  The  acetate  of 
cellulose  so  obtained  is  soluble  in  ether  and  chloroform  (Lederer).  At  Sthamer's 
chemical  works  (Hamburg)  acetate  of  cellulose  is  prepared  by  heating  a  mixture 
of  hydrocellulose,  acetic  acid,  acetyl  chloride,  and  sulphuric  acid  to  65°-7o°  C. 
An  acetate  of  cellulose  soluble  in  alcohol  and  pyridin  is  obtained  by  heating  a 
mixture  of  cellulose,  acetic  anhydride,  and  sulphuric  acid  to  45°  C.  (Farbenfa- 
briken  vorms.  Fr.  Bayer  &  Co.  of  Elberfeld).  Miles  and  Pierce  (Brooklyn)  obtain 
it  by  heating  a  mixture  of  cellulose,  acetic  anhydride,  acetic  acid,  and  sulphuric 
acid  to  70°  C.  Landsberg  substitutes  phosphoric  acid  for  sulphuric  acid  in  the 
preceding  mixture.  Acetate  of  cellulose  has  also  been  prepared  by  warming  a 
mixture  of  cellulose,  acetic  acid,  acetic  anhydride,  and  a  mixture  of  phenol-sodium 
sulphonate  and  phenol-sulphonic  acid,  or  of  sodium  naphtholate  and  naphthol- 
sulphonic  acid  (Little,  Walker  &  Mork,  Boston).  Cellulose  may  also  be  acetylized 


CHEMICAL  PROPERTIES   OF  COTTON;    CELLULOSE     281 

The  tetracetate  has  received  a  number  of  commercial  applications 
for  the  production  of  films  and  for  waterproofing.  By  the 
action  of  nitric  acid  under  varying  conditions,  a  number  of 
cellulose  nitrates  (improperly  called  nitrocelluloses)  have  been 
prepared  which  have  received  numerous  applications  (see 
pyroxylin).*  Concentrated  sulphuric  acid  reacts  with  cellulose 
to  form  at  first  a  cellulose  sulphate;  this  subsequently  undergoes 
decomposition  with  a  consequent  hydrolysis  of  the  cellulose 
molecule  and  the  formation  of  amyloid.  Aceto-sulphates  of 
cellulose  have  been  prepared  by  the  joint  action  of  acetic  acid, 
acetic  anhydride,  and  sulphuric  acid  on  cellulose,  f 

For  the  preparation  of  what  Cross  and  Bevan  term  the  normal 
cellulose  aceto-sulphate,  to  which  the  formula  ^CeHrC^)  • 
(SO4)-(C2H302)io  is  ascribed,  16  grams  of  dry  cotton  are 
stirred  for  twenty  minutes  at  30°  C.  in  100  cc.  of  a  mixture  of 
equal  parts  of  glacial  acetic  acid  and  acetic  anhydride  containing 
4.5  per  cent  by  weight  of  sulphuric  acid.  After  standing  for 
one  hour,  a  homogeneous,  translucent,  and  viscous  solution 
is  obtained,  which  is  precipitated  on  being  poured  into  water  as 
a  semi-translucent,  gelatinous  hydrate,  which  is  soluble  in  alcohol. 
By  using  less  sulphuric  acid  the  product  obtained  is  insoluble 
in  alcohol. 

Although  cellulose  is  comparatively  inert  to  the  majority  of 
chemical  reagents,  it  has  a  powerful  attraction  for  certain 
salts  held  in  solution  and  will  absorb  them  completely.  This 
power  of  absorption  is  especially  marked  toward  salts  of  vana- 
dium, these  being  completely  separated  from  solutions  contain- 
ing only  one  part  of  the  salt  per  trillion. 

Besides  cellulose  itself,  there  are  a  number  of  derived  sub- 
stances which  are  known  as  compound  celluloses.  These  are 
classified  into  three  general  groups: 

(a)  Pectocelluloses,  related  to  pectin  compounds  of  vegetable 

by  means  of  a  mixture  in  nitrobenzene  solution  of  acetyl  chloride  and  chloride  of 
zinc  or  magnesium,  in  the  presence  of  pyridin  or  quinolin  (Wohl,  Charlottenburg). 

*  For  a  thorough  and  detailed  description  of  the  cellulose  nitrates  and  the 
industries  based  thereon  consult  Worden,  Nitrocellulose  Industry,  2  vols.,  1911. 

f  See  Cross,  Bevan  &  Briggs,  Berichte,  1905,  p.  1859. 


282  THE  TEXTILE  FIBRES 

tissues;    represented  among  the  fibres  by  raw  flax;    resolved 
by  hydrolysis  with  alkalies  into  pectic  acid  and  cellulose.* 

(b)  Lignocelluloses ,  forming  the  main  constituent  of  woody 
tissue  and  represented  among  the  fibres  by  jute  ;    resolved  by 
chlorination  into  chlorinated  derivatives  of  aromatic  compounds 
soluble  in  alkalies  and  cellulose.! 

(c)  Adipocelluloses,    forming    the    epidermis    or    cuticular 
tissue  of  fibres,  leaves,  cork,  bark,  etc.;    resolved  by  oxidation 
with  nitric  acid  into  derivatives  similar  to  those  of  the  oxida- 
tion of  fats  and  cellulose.! 

Fremy  groups  the  various  celluloses  and  their  derived 
bodies  in  the  following  manner,  which  is  based  on  a  chemical 
classification:  (a)  celluloses,  including  normal  cellulose,  para- 
cellulose,  and  metacellulose ;  (b)  vasculose  (identical  with 
lignocellulose) ;  (c)  cutose;  (d)  pectose. 

4.  Chemical  Reactions  of  Cotton  ;  Heat. — Cotton  itself 
presents  the  same  general  reactions  and  chemical  properties 
as  cellulose.  It  is  capable  of  standing  rather  high  temperatures 
without  decomposition  or  alteration;  though  it  appears  that 
when  cotton  is  subjected  to  a  temperature  of  160°  C.,  whether 
moist  or  dry  heat,  a  dehydration  of  the  cellulose  takes  place, 
accompanied  by  a  structural  disintegration  of  the  fibre.  This 
fact  has  an  important  bearing  on  the  singeing,  calendering, 
and  other  finishing  processes  where  high  temperatures  are  used. 
Within  the  limits  of  the  temperatures  to  be  met  with  in  the 
usual  processes  of  drying,  a  dry  heat  has  little  or  no  influence 
on  the  substance  of  the  cotton  fibre. §  At  250°  C.  cotton  begins 

*  The  pectocelluloses  are  somewhat  richer  in  oxygen  than  normal  cellulose 
(cotton).  When  boiled  with  dilute  alkalies  they  are  easily  resolved  into  cellulose, 
the  pectin  substances  being  converted  into  soluble  derivatives.  This  is  the 
reaction  that  takes  place  in  the  bleaching  of  linen. 

t  Lignocellulose  consists  of  about  75  per  cent  cellulose  and  25  per  cent  of 
lignin.  Jute  absorbs  iodin,  forming  an  unstable  compound.  This  reaction  is 
employed  in  the  quantitative  determination  of  lignocelluloses  in  combination  with 
other  forms  of  cellulose.  Lignocelluloses  also  hydrolyze  much  more  readily  than 
normal  cellulose. 

\  The  adipocelluloses  are  cellular  rather  than  fibrous  in  structure.  They  con- 
tain more  carbon  and  less  oxygen  than  normal  cellulose. 

§When  cotton  yarn  is  dried  for  12  hours  at  70°  C.  (160°  F.)  it  loses  about 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE      283 


to  turn  brown;  and  when  ignited  in  the  air  it  burns  freely, 
emitting  an  odor  faintly  suggesting  acrolein,  but  without 
the  characteristically  empyreumatic  odor  of  burning  animal 
fibres.  When  subjected  to  dry  distillation  cotton  is  decomposed 
into  methane,  ethane,  water,  methyl  alcohol,  acetone,  acetic 
acid,  carbon  dioxide,  pyrocatechol,  etc.* 

5  per  cent  in  tensile  strength,  and  also  much  of  its  elasticity,  becoming  harsh 
and  brittle.  It  rapidly  regains  its  hygroscopic  moisture,  however,  on  exposure 
to  the  air  and  recovers  its  original  strength.  Heated  from  90°  to^ioo0  C.  (195° 
to  212°  F.)  cotton  loses  about  6  to  8  per  cent  in  weight;  from  100°  to  120°  C. 
about  0.5  per  cent  more.  Above  120°  C.  the  loss  is  very  slow,  and  indicates 
decomposition;  at  180°  C.  (360°  F.)  it  will  have  lost  about  i  per  cent  more  in 
weight,  and  the  fibre  begins  to  acquire  a  yellowish  color  showing  the  beginning 
of  carbonization. 

*The  following  table  gives    the    results  of  the  dry  distillation   of    cotton 
(Ramsay  and  Chorley,  Jour.  Soc.  Chem.  Ind.,  1892,  p.  872): 


Distillate. 

Raw  Cotton. 
Per  Cent. 

Bleached  Cotton. 
Per  Cent. 

Cotton  Cellulose 
from  Viscose. 
Per  Cent. 

Solids  and  carbon 

22 

24  44 

42  .O 

Liquids 

46 

<CI    II 

44  -° 

Carbon  dioxide  
Other  gases            .  . 

II 

IO 

7-77 

6.68 

7-4 
6.6 

The  composition  of  the  liquid  distillate  per  ico  parts  of  cotton  is  as  follows: 


Substance. 

Raw  Cotton. 
Per  Cent. 

Bleached  Cotton. 
Per  Cent. 

Cotton  Cellulose 
from  Viscose. 
Per  Cent. 

Acetic  acid  
Methyl  alcohol         .            ... 

I-3I 

7   O7 

2  .  II 

IO    24 

2  .00 

IO    24 

Tars 

I  2    OO 

I  3    ^  3 

I  2      22 

The  composition  of  the  gaseous  distillate  is  as  follows: 


Substance. 

Raw  Cotton. 
Per  Cent. 

Bleached  Cotton. 
Per  Cent. 

Cotton  Cellulose 
from  Viscose. 
Per  Cent. 

Carbon  dioxide 

76  oo 

C4    j4 

So 

Oxygen                    

*,  66 

8  so 

4 

Residual  gases                       .    . 

10   44 

27      26 

16 

284  THE   TEXTILE  FIBRES 

5.  Action   of   Water. — Cotton   is   unaltered    and    insoluble 
in  cold  and  boiling  water.*     When  cotton  is  heated  for  eight 
hours  under  pressure  at  150°  C.  (300°  F.,  corresponding  to  4.75 
atmospheres)  it  is  not  apparently  affected.     At  160°  C.  (320° 
F.,    corresponding    to    6.15    atmospheres    pressure),    however, 
the  fibre  appears  to  undergo  some  alteration,  f     If  air  is  also 
present  the  effect  is  very  pronounced  at  170°  C.  (340°  F.,  cor- 
responding to   7.85   atmospheres  pressure).     Hydrocellulose  is 
apparently  formed  when  cotton  is  heated  with  water  under  a 
pressure  of  20  atmospheres.     When  cotton  is  subjected  to  the 
action  of  steam  under  high  pressures  the  fibre  undergoes  dis- 
integration, the  effect,  no  doubt,  of  hydrolytic  action. 

6.  Action  of  Cuprammonium  Solution.     Like  cellulose  itself, 
cotton   is   dissolved    by   Schweitzer's   reagent,   though   under 
ordinary  conditions  its  solution  is  a  rather  slow  process.     In 
order  to  dissolve  cotton  most  effectively  in  ammoniacal  copper 
oxide,  it  is  recommended  to  treat  the  raw  cotton  with  a  strong 
solution  of  caustic  soda  until  the  fibres  swell  up  and  become 
translucent;   squeeze  out  the  excess  of  liquid,  and  wash  the  cot- 
ton with  strong  ammonia  water;   then  treat  with  the  solution  of 
ammoniacal  copper  oxide  and  the  cotton  will  be  found  to  dis- 
solve quite  rapidly.     This  solution  may  furthermore  be  filtered 
and  diluted  with  water.     The  use  of  this  solution  for  the  pro- 
duction of  lustra-cellulose  filaments  has  received  some  degree 
of  commercial  application  (see  Pauly  silk,   Chapter  XV).      This 
reaction  is  also  utilized  in  the  preparation  of  a  fabric  known  as 
Willesden  canvas;  the  cotton  fabric  is  passed  through  a  solution 
of   ammoniacal   copper   oxide,   whereby   the   surface   becomes 

*  Treatment  in  boiling  water  for  12  hours  appears  to  increase  the  dyeing 
effect  of  cotton  for  substantive  dyes  and  to  decrease  it  for  basic  dyes.  (Hiibner 
and  Pope,  Jour.  Soc.  Chem.  hid.,  1904,  p.  404). 

f  A  considerable  rise  in  temperature  is  noted  when  cotton  is  wetted  with 
water.  This  effect,  however,  does  not  appear  to  be  due  to  chemical  action,  as 
the  same  effect  is  obtained  on  wetting  finely  divided  inert  solids.  Masson  (Proc. 
Roy.  Soc.,  vol.  74,  p.  230)  has  made  a  detailed  study  of  the  conditions  which  give 
rise  to  these  phenomena.  Martine  (Phil.  Mag.,  vol.  47,  p.  329)  also  gives  a 
study  of  this  effect.  According  to  Masson  the  action  is  due  to  a  distillation 
effect,  whereas  Martine  considers  that  the  liquids  are  absorbed  by  the  solids, 
passing  into  the  solid  state  themselves.  (See  also  Phil.  Mag.,  vol.  50,  p.  618.) 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     285 

coated  with  a  film  of  gelatinized  cellulose  containing  a  con- 
siderable amount  of  copper  oxide.  On  subsequent  hot  pressing 
this  film  is  fixed  on  the  surface  of  the  material  as  a  substantial 
coating,  which  is  said  to  make  the  canvas  water-proof  and 
render  it  unaffected  by  mildew  and  insects. 

7.  Action    of    Zinc    Chloride. — Concentrated    solutions    of 
zinc  chloride  are  capable  of  dissolving  cotton,  but  only  after 
a  prolonged  digestion  at  about  100°  C.,  though  by  first  treating 
the  cotton  with  caustic  alkali  the  solution  takes  place  in  the 
cold.     The  product  so  obtained  has  received  several  industrial 
applications;    vulcanized  fibre  is   prepared   by   treating  paper 
with  a  concentrated  solution  of  zinc  chloride,*  and  the  result- 
ing gelatinous  mass  is  manufactured  into  various  articles,  such 
as  blocks,  sheets,  etc.f    The  chief  difficulty  encountered  is  the 
subsequent  removal  of  the  zinc  salt,  which  necessitates  a  very 
lengthy  process  of  washing.     The  material  may  be  rendered 
water-proof  by  a  further  process  of  nitration.  {    The  solution 
has   also  been   suggested  for  use   as    a    thickening   agent    in 
calico-printing.     It  has  also  been  used  for  the  production  of 
lustra-cellulose    or    artificial    silk    and    of    incandescent-lamp 
filaments. 

8.  Action    of    Acids. — With  mineral   acids   cotton  exhibits 
practically  the  same  general  reactions  as  pure  cellulose.     Con- 
centrated   sulphuric    acid    produces    amyloid    in    the    manner 
previously  mentioned,  and  this  fact  is  utilized  in  the  preparation 
of  what  is  known  as  vegetable  parchment.     Unsized  paper  is 
rapidly    passed    through    concentrated    sulphuric    acid,    then 
thoroughly  washed  and  dried.     The  effect  of  this  treatment  is 
to  cause  the  formation  on  the  surface  of  the  paper  of  a  layer 
of  gelatinous  amyloid,  which  on  subsequent  pressing  and  drying 

*  One  part  of  paper  is  treated  with  four  parts  of  zinc  chloride  solution  of  65° 
to  75°  Be.  until  the  fibres  are  partially  gelatinized,  when  the  sheets  are  then 
pressed  together  into  very  compact  masses.  (See  Hofmann,  Handb.  d.  Papierfab., 
p.  170.) 

f  Vulcanized  fibre  is  quite  hard,  having  the  consistency  of  horn;  but  by  the 
addition  of  deliquescent  substances  such  as  glycerin  or  glucose  a  pliable  product 
may  be  obtained. 

J  Hofmann,  ibid.,  p.  1703. 


286  THE  TEXTILE  FIBRES 

gives  a  tough  membranous  surface  to  the  paper  resembling  true 
parchment.  This  renders  the  paper  grease-proof  and  water- 
proof, and  increases  its  tensile  strength  considerably.  Artificial 
horse-hair  has  been  prepared  in  a  similar  manner  from  certain 
Mexican  grasses.  These  latter  are  steeped  for  a  short  time  in 
concentrated  sulphuric  acid,  and  become  parchmentized  thereby, 
so  that  on  being  subsequently  washed  and  combed  they  assume 
an  appearance  very  much  resembling  horse-hair,  and  are  said 
to  possess  even  greater  elasticity  than  horse-hair  itself.  In 
place  of  strong  sulphuric  acid  a  solution  of  zinc  chloride  may  be 
used  with  similar  results.  Amyloid  appears  also  to  be  a  product 
of  natural  plant  growth,  as  its  presence  has  been  detected  in 
the  walls  of  vegetable  cells;  it  may  be  recognized  by  giving  a 
blue  color  with  iodin. 

Under  proper  conditions  of  treatment  concentrated  mineral 
acids  have  a  mercerizing  or  hydrating  action  on  cotton.  Sul- 
phuric acid  at  the  ordinary  temperature  begins  to  exert  a 
mercerizing  effect  at  a  strength  of  35°  Be.  Acid  of  49° 
to  55°  Be.  acts  much  in  the  same  manner  as  caustic  soda;  the 
fibre  becomes  mercerized  and  possesses  an  increased  affinity 
for  dyestuffs,  and  acquires  an  increased  lustre  and  strength. 
The  same  is  also  true  of  concentrated  solutions  of  phosphoric 
acid  (59°  Be.).  If  the  action,  however,  of  the  acids  is  at  all 
prolonged,  complete  hydrolysis  and  destruction  of  the  fibre 
take  place. 

Very  dilute  solutions  of  sulphuric  acid,  especially  in  the  cold, 
have  no  appreciable  action  on  cotton.  But  if  the  fibre  is 
impregnated  with  such  a  solution  and  then  allowed  to  dry  it 
becomes  tendered;  this  is  owing  to  the  gradual  concentration 
of  the  acid  on  drying,  and  hydrolysis  of  the  fibre.  Elevated 
temperatures  also  cause  the  dilute  acid  to  attack  the  fibre 
much  more  quickly  and  severely  than  otherwise.* 

The  action  of  dilute  mineral  acids  on  cotton  seems  to  be 

*  According  to  Biittner  and  Neuman  (Zeit.  ang.  Chem.,  1908,  p.  2609)  when 
cotton  is  treated  with  dilute  sulphuric  acid  of  sp.  gr.  1.45-1.53  a  mixture  is 
obtained  consisting  probably  of  hydrocellulose  and  oxycellulose  with  more  or 
less  unchanged  cellulose. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     287 

one  of  hydrolysis,  whereby  a  molecular  change  occurs  in  the 
fibre  substance.  This  hydrolytic  action  is  supposed  to  result 
in  the  formation  of  hydrocellulose,  having  the  formula 
2C6HioO5-H2O.*  Acetic  acid  has  but  small  hydrolytic  action, 
and  consequently  has  little  effect  on  cotton. 

In  all  dyeing  and  bleaching  operations  where  the  use  of  acid 
may  be  required,  the  above  facts  should  always  be  borne  in 
mind;  the  temperature  of  the  acid  baths  should  be  not  above 
70°  F.,  and  the  acid  strength  should  not  be  more  than  2  per 
cent.  Where  higher  temperatures  are  necessary,  organic  acids 
should  be  substituted  for  mineral  acids  wherever  possible. 
Acetic  acid,  for  instance,  is  often  used.  Whenever  cotton  is 
treated  with  acid  solutions  or  with  salts  of  an  acid  nature,  or 
which  are  liable  to  decompose  with  liberation  of  acid,f  all  of 
the  acid  should  be  removed  from  the  fibre  or  properly  neutral- 
ized before  drying,  else  the  material  will  be  tendered  and  prob- 
ably ruined.  The  action  of  dilute  acid  on  cotton  is  probably 
a  hydrolysis  of  the  cellulose  molecule,  with  the  formation 
of  hydrocellulose  causing  a  structural  disorganization  of  the 
fibre.  Hydrochloric  acid  has  an  effect  similar  to  sulphuric 
acid,  and  the  same  remarks  concerning  the  use  of  this  latter 
acid  in  connection  with  cotton  also  hold  true  for  the  former. 


*  The  action  of  the  acid  no  doubt  takes  place  in  several  phases,  as  shown 
by  the  subsequent  acetylation  of  the  products.  It  is  quite  certain  that  between 
the  body  Ci2H2oOio-H2O,  which  should  correspond  to  the  hydrocellulose  of  Girard, 
and  ordinary  cellulose,  CizHzoOio,  there  exists  a  series  of  hydrocelluloses  comprised 
under  the  general  formula,  (CsHioOo^-HaO. 

t  The  tendering  of  cotton  dyed  with  sulphur  colors,  which  is  sometimes  noticed, 
is  due  to  the  presence  of  free  sulphuric  acid  arising  from  the  oxidation  of  the 
dyestuff.  This  liberation  of  sulphuric  acid  is  accelerated  by  exposure  to  heat. 
Holden  (Jour.  Soc.  Dyers  6*  Col.,  1910,  p.  76)  by  exposing  samples  of  cotton 
dyed  with  various  sulphur  dyestuffs  to  a  temperature  of  i2o°C.  for  20  hours,  found 
that  the  material  lost  in  strength  from  39  to  78  per  cent,  and  the  amount  of  free 
sulphuric  acid  liberated  varied  from  0.027  to  0.078  per  cent  on  the  weight  of  the 
cotton.  Methods  for  preventing  this  tendering  effect  of  the  sulphur  dyes  rely 
for  their  efficiency  either  on  assisting  the  oxidation  of  the  dyestuff  (as  in  the 
treatment  with  bichromates),  or  on  after-treating  the  dyed  material  with  salts 
capable  of  neutralizing  free  mineral  acids.  These  latter  compounds  usually 
have  the  disadvantage  of  being  soluble  in  water.  Holden  recommends  the  pre- 
cipitation of  calcium  tannate  on  the  dyed  material. 


288  THE  TEXTILE  FIBRES 

9.  Hydrocellulose. — This  is  the  compound  resulting  from 
the  hydrolysis  of  cellulose  through  the  action  of  dilute  acids. 
It  appears  to  be  a  combination  of  cellulose  with  one  molecule 
of  water,  and  has  been  given  the  formula  Ci2H22On.*  As 
previously  pointed  out  the  formation  of  hydrocellulose  from 
cotton  results  in  structural  disintegration  so  that  the  fibre  may 
easily  be  reduced  to  a  powder.  Hydrocellulose  is  also  of  con- 
siderable technical  importance,  as  it  is  much  more  reactive  than 
ordinary  cellulose,  and  so  is  employed  for  the  production  of  the 
nitric  and  acetic  acid  compounds  of  cellulose,  as  the  hydrocellulose 
compounds  are  much  more  soluble  in  the  solvents  employed. 

Hydrocellulose  may  be  prepared  by  treating  a  mixture  of 
cotton  and  potassium  chlorate  with  hydrochloric  acid  at  a  tem- 
perature of  6o°-7o°  C.f  The  product  obtained  in  this  manner 
is  in  the  form  of  a  white  powder  and  is  very  resistant  to  further 
hydrolysis  by  acids  and  alkalies. 

Hydrocellulose  may  also  be  prepared  in  the  following 
manner  J :  Chlorin  gas  is  passed  into  glacial  acetic  acid  until 
the  solution  is  perceptibly  yellow.  Then  5  parts  of  this  acid 
mixture  is  heated  to  6o0-yo0  C.,  and  thoroughly  mixed  with  i 
part  of  cotton.  In  a  short  time  the  cotton  swells  up  considerably 
and  becomes  viscous.  The  heating  is  continued  until  a  sample 
is  found  to  be  completely  miscible  with  water.  The  product 
is  then  washed  until  neutral  and  then  dried. 

Hydrocellulose    is    to    be    distinguished    from    cellulose    in 

*  See  Stern  (Jour.  Chem.  Soc.,  1904,  p.  336).  When  a  cellulose  fibre  is 
exposed  to  the  action  of  dilute  acids  under  certain  conditions,  its  tenacity  is 
destroyed,  and  it  falls  to  a  powder  which  has  been  called  hydrocellulose,  and 
stated  to  have  the  empirical  formula,  C^H^On.  When  the  above  reaction  takes 
place,  however,  instead  of  a  gain  in  weight  as  theory  would  indicate,  there  is 
invariably  a  loss  and  a  small  amount  of  soluble  matter  is  formed,  a  portion  of  which 
in  all  probability  is  d-glucose.  The  elementary  composition  of  the  powder  is 
also  shown  to  be  identical  with  that  of  cellulose,  the  previous  statements 
on  this  point  being  claimed  to  be  founded  on  faulty  experimental  methods.  A 
hydrated  cellulose  is  not  formed  under  these  conditions,  but  a  hydrolysis  takes 
place  similar  to  that  undergone  by  other  carbohydrates  under  comparable  con- 
ditions. 

t  Stahmer's  method.     Oxycellulose  is  also  likely  to  be  produced  in  this  reaction. 

t  Stahmer,  Eng.  Pat.  19,039  of  1900. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     289 

that  it  is  colored  blue  by  a  solution  of  zinc  chlor-iodide  or  with 
a  solution  of  iodin  in  potassium  iodide.  Hydrocellulose  also 
reduces  Fehling's  solution  and  an  ammoniacal  solution  of  silver 
nitrate.* 

Hydrocellulose  is  not  to  be  confused  with  hydracellulose 
(see  p.  339).  The  latter  contains  only  water  of  hydration, 
whereas  the  former  is  a  hydrolyzed  product  of  cellulose  inter- 
mediate between  normal  cellulose  and  completely  hydrolyzed 
cellulose  (sugar). 

Hydrocellulose  is  characterized  by  its  reducing  power  and 
its  solubility  in  caustic  soda  solution.  Like  cellulose  itself, 
hydrocellulose  exhibits  great  affinity  for  water,  giving  hydrates 
of  hydrocellulose.  t 

10.  Action  of  Nitric  Acid. — While  dilute  solutions  of  nitric 
acid  have  a  similar  effect  on  cotton  to  other  mineral  acids, 
strong  nitric  acid  has  a  somewhat  different  action.  {  It  com- 
pletely decomposes  cotton,  in  common  with  other  forms  of 
cellulose,  oxidizing  it  to  various  products  among  which  is 

*  This  is  due  to  the  presence  of  free  carbonyl  groups  in  the  molecule  of  hydro- 
cellulose. 

f  The  extent  of  the  hydration  of  hydrocellulose  is  determined  by  the  degree 
of  hydrolysis;  that  is  to  say,  the  more  hydroxyl  groups  (OH)  a  cellulose  con- 
tains, the  more  water  it  will  combine  with. 

J  The  action  of  nitric  acid  on  cotton  fabrics  appears  to  be  a  peculiar  one.  The 
following  observations  in  this  respect  have  been  recorded  by  Knecht:  Bleached 
calico  steeped  for  fifteen  minutes  in  pure  nitric  acid  at  80°  Tw.,  washed  and 
dried,  showed  a  considerable  contraction,  amounting  to  about  24  per  cent;  the 
tensile  strength  alsD  increased  78  per  cent.  Unbleached  yarn,  treated  in  the 
same  manner,  also  showed  a  considerable  increase  of  tensile  strength,  and  a  pro- 
portional contraction  in  length.  Weaker  acids  did  not  show  these  results,  the 
fibre  being  tendered  instead  of  being  strengthened.  Analysis  proved  that  7.7  per 
cent  of  nitrogen  was  present,  showing  that  about  two  molecules  of  the  acid  had 
combined  with  the  cotton.  The  shrinkage,  gain  in  strength,  microscopical 
appearance,  etc.,  of  the  treated  material,  all  go  to  show  that  in  addition  to  the 
nitration  a  mercerizing  effect  has  been  produced.  This  appears  in  the  fact  that 
the  material  exhibits  a  strongly  increased  affinity  for  many  dyestuffs,  especially 
the  direct  cotton  colors  and  some  of  the  acid  dyes;  while  by  reason  of  its  not 
showing  any  increased  affinity  for  the  basic  colors  there  is  proof  that  oxycellulose 
has  not  been  produced.  This  action  of  strong  nitric  acid  on  cellulose  has 
been  utilized  for  the  preparation  of  toughened  filter-papers  which  are  required  to 
staid  high  fluid  pressures.  The  filter-paper  is  immersed  in  concentrated  nitric 
acid  for  a  brief  period  and  then  well  washed. 


290  THE  TEXTILE  FIBRES 

oxalic  acid.  When  boiled  with  moderately  concentrated  nitric 
acid  cotton  is  converted  into  oxycellulose,*  a  structureless, 
friable  substance  possessing  a  great  affinity  for  basic  dyestuffs. 
When  mixed  with  concentrated  sulphuric  acid,  however,  the 
action  of  nitric  acid  on  cotton  is  totally  different,  the  cellulose 
being  converted  into  a  nitrated  body,  though  the  physical 
appearance  of  the  fibre  is  not  appreciably  altered. f  The  exact 
nature  of  the  nitrated  compound  will  depend  on  the  conditions 
of  treatment.t  Several  nitrated  celluloses  are  known  and  possess 
commercial  importance;  they  are  classified  under  the  general 
name  of  pyroxylins.  Guncotton,  a  hexanitrated  cellulose, 
is  the  most  highly  nitrated  product,  and  is  used  as  a  basis  of 
many  explosives.  Soluble  pyroxylin  is  a  trinitrated  cellulose; 
its  solution  in  a  mixture  of  alcohol  and  ether  is  called  collodion 
and  is  employed  in  surgery  and  photography.  Another 
derivative,  supposed  to  be  a  tetranitrated  cellulose,  is  also 
soluble  in  ether-alcohol,  and  its  solution  has  been  utilized  for 
the  production-  of  lustra-cellulose  filaments.  By  dissolving 
nitrated  cellulose  in  molten  camphor  a  substance  known  as 
celluloid  is  formed.  § 

*  Cross  and  Bevan,  Jour.  Chem.  Soc.,  1883,  p.  22. 

f  Bronnert  (Rev.  Gen.  Mat.  Col.,  1900)  states  that  nitration  of  the  cotton  fibre, 
even  to  the  extent  of  introducing  80  per  cent  of  NC>2  groups,  does  not  appreciably 
alter  the  visible  structure  or  breaking  strain  of  the  thread. 

J  If  nitrated  cotton  be  examined  under  the  microscope,  a  considerable  altera- 
tion in  its  appearance  will  be  observed.  The  fibres  have  a  much  thicker  cell-wall, 
and  are  consequently  stiffer  than  those  of  ordinary  cotton.  The  lumen  has  either 
vanished  entirely  or  become  very  much  contracted,  and  this  appears  to  be  due 
to  the  swelling  of  the  cell-walls.  In  the  walls  of  the  fibre  there  will  also  be  noticed 
numerous  fractures  or  cracks  which  often  assume  a  spiral  shape.  The  nitration 
has  evidently  rendered  the  fibre  much  more  brittle  and  has  decreased  its  elasticity. 

§  Hoepfner  has  prepared  porous  acid-proof  fabrics  to  be  employed  for  filter- 
ing purposes  in  electrolytic  work  by  using  cotton  yarn  which  has  been  nitrated. 
The  latter  can  be  woven  along  with  asbestos,  glass,  or  other  mineral  fibres  in  the 
making  of  the  fabric.  According  to  Claessen  acid-proof  filter  cloths  may  be 
prepared  by  first  immersing  the  cloth  in  cold  nitric  acid  of  4o°-5o°  Be.,  then 
in  concentrated  sulphuric  acid  of  60°  Be.,  finally  washing  with  water  until  neutral. 
By  this  means  a  superficial  nitration  only  is  effected.  (See  Zeit.  ang.  Chem., 
1906,  p.  317.)  F.  Bayer  &  Co.  (see  U.  S.  Pat.  850266  of  1908)  state  that  com- 
pletely nitrated  cloth  may  be  produced  by  immersion  first  in  nitric  and  then  in 
sulphuric  acid  and  that  the  cloth  so  prepared  is  superior  in  quality  and  strength 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     291 


The  following  are  descriptions  of  the  principal  nitrated 
products  of  cotton  cellulose.*  In  the  formulas  given  the 
cellulose  unit  group  is  taken  as  Ci2H2oOio-t 

Cellulose  hexanitrate,  or  guncotton,  Ci2Hi4O4(N03)e,  is 
made  by  the  use  of  3  parts  nitric  acid  of  sp.  gr.  1.5  and  i  part 
sulphuric  acid  of  sp.  gr.  1.84.  The  cotton  is  immersed  in  this 
mixture  for  twenty-four  hours  at  a  temperature  not  above 
10°  C.;  100  parts  of  cellulose  yield  about  175  parts  of  the 
nitrate.  This  nitrate  is  insoluble  in  alcohol,  ether,  or  in  mix- 
to  that  formed  from  weaving  threads  made  from  nitrocellulose  solutions,  being 
nearly  twice  as  strong  and  more  resistant  to  acids  and  chlorine  while  at  the  same 
time  being  open  and  porous.  To  produce  solid  cloths  which  are .  acid-proof , 
Bachrach  (U.  S.  Pat.  692102,  of  1902)  recommends  the  addition  of  graphite  or 
bitumen.  It  is  said  that  10  per  cent  of  either  of  these  will  produce  a  cloth  which 
will  successfully  resist  long  contact  with  corrosive  chemicals.  Nitrocellulose 
may  be  blended  with  the  graphite  or  bitumen  by  use  of  an  acid  resisting  solvent 
known  as  "picamer"  (Greening,  Eng.  Pat.  22019  of  ^94)  which  will  dissolve 
nitrate  of  cellulose.  Picamer  is  obtained  by  fractionating  wood  tar  distillate 
with  chromic  acid  or  alkaline  potassium  bichromate. 

*  See  Cross  and  Be  van,  Cellulose. 

t  Vielle  has  studied  the  nitration  of  cotton  with  different  concentrations  of 
acid  with  the  following  results: 


Density  of 
Nitric  Acid. 


1.502 
1-497 

1.496) 
1.492  \ 
1 . 490  J 

I.488l 
1.4*3  / 


1.476] 
1.472  [ 
1.469  J 

1.463 
1.460 

1-455 
1.450 


Product  Obtained. 

I  Structural  features  of  cotton  preserved;    soluble 
in  acetic  ether;  not  in  ether-alcohol: 

C24H20(N03H)1oOlo. 

Appearances  unchanged;  soluble  in  ether-alco- 
hol; collodion  cotton: 

C24H22(N03H)9Ou,     C24H24(N03H)8012. 

[  Fibre  still  unresolved;  soluble  as  above,  but  solu- 
\      tions  more  gelatinous  and  thready: 
C24H26(N03H)7013. 

Dissolve  cotton  to  viscous  solution;  products 
precipitated  by  water;  gelatinized  by  acetic 
ether;  not  by  ether  alcohol : 

C24H28(N03H)6On. 

Friable  pulp;  blued  strongly  by  iodin  in  potas- 
sium iodide  solution;  insoluble  in  alcohol  sol- 
vents: 

C24H30(N03H)5015,     C24H32(N03H)<016. 


292  THE  TEXTILE  FIBRES 

tures  of  both,  in  glacial  acetic  acid,  or  methyl  alcohol;  slowly 
soluble  in  acetone.  Ordinary  guncotton  may  contain  as 
much  as  12  per  cent  of  nitrates  soluble  in  ether-alcohol 
mixture. 

Cellulose  penlanitrate,  C^HioOsCNOs^,  is  prepared  by 
dissolving  guncotton  (the  hexanitrate)  in  nitric  acid  at  80°  to 
90°  C.,  and  .precipitating  by  the  addition  of  sulphuric  acid 
after  cooling  to  o°  C.  The  precipitate  consists  of  the  penta- 
nitrate,  and  is  purified  by  washing  with  water,  then  with  alcohol, 
dissolving  in  ether-alcohol,  and  reprecipitating  with  water. 
The  pentanitrate  is  insoluble  in  alcohol,  is  slightly  soluble  in 
acetic  acid,  and  readily  so  in  ether-alcohol;  by  treatment 
with  strong  caustic  potash  it  is  converted  into  the  dinitrate. 

Cellulose  tetra-  and  tri-nitrates  (collodion  pyroxylin)  are 
formed  simultaneously  when  cotton  is  treated  with  a  more 
dilute  acid  and  at  higher  temperatures,  and  for  a  shorter  time 
than  in  the  preparation  of  the  hexanitrate.  As  these  two 
nitrates  are  soluble  to  the  same  extent  in  ether-alcohol,  acetic 
ether,  and  methyl  alcohol,  it  is  not  possible  to  separate  them. 
When  treated  with  a  mixture  of  concentrated  nitric  and  sul- 
phuric acids,  they  are  both  converted  into  penta-  arid  hexa- 
nitrates;  caustic  potash  and  ammonia  convert  them  into  the 
dinitrate. 

Cellulose  dinitrate,  CisHiaOsCNOs^,  is  formed  through  a 
partial  saponification  of  the.  higher  nitrates  by  the  action  of 
caustic  potash,  and  also  by  the  action  of  hot  dilute  nitric  acid 
on  cellulose.  The  dinitrate  is  very  soluble  in  ether-alcohol, 
acetic  ether,  and  in  absolute  alcohol. 

The  action  of  hydrofluoric  acid  on  cotton  and  other  vegetable 
fibres  appears  to  be  a  peculiar  one;  a  transparent,  tough, 
flexible  water-proof  material  being  obtained.  The  product 
does  not  appear  to  resemble  parchment  obtained  by  the  action 
of  sulphuric  acid.  It  is  used  as  an  insulating  •  material 
and  for  making  the  carbon  filaments  of  incandescent  electric 
lamps. 

ii.  Action  of  Organic  Acids. — Organic  acids  involution, 
even  when  moderately  concentrated,  do  not  appear  to  have 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     293 

any  injurious  action  on  cotton.  The  non-volatile  acids,  how- 
ever, such  as  oxalic,  tartaric,  and  citric  acids,  when  allowed 
to  dry  into  the  fibre,*  act  much  in  the  same  manner  as  mineral 
acids,  especially  at  elevated  temperatures.!  Acetic  acid, 
however,  being  volatile,  exerts  no  destructive  action;  hence 
this  latter  acid  is  particularly  suitable  for  use  in  the  dyeing  and 
printing  of  cotton  goods,  where  the  use  of  an  acid  is  requisite.  J 


*  The  effect  of  certain  acids  on  the  strength  of  cotton  is  an  important  factor  in 
printing.  The  following  table  shows  the  degree  of  weakening  caused  by  various 
acids,  strips  of  calico  being  printed  with  tragacanth  pastes  containing  20  grams 
of  oxalic  acid  per  litre,  or  an  equivalent  amount  of  the  other  acids,  and  in  the 
first  case  exposed  for  four  hours  to  the  ordinary  temperature,  and  in  the  second 
case  steamed  for  one  hour: 


Acid. 

i. 

II. 

Oxalic    

25      per  cent 

25      per  cent 

Tartaric 

r               " 

10 

Ortho-phosphoric  

i-5 

15 

Meta-phosphoric  

31-5        " 

35 

Pyro-phosphoric  

35-0        " 

35-5       " 

Phosphorous  

27            " 

28 

Under  similar  conditions  sulphocyanic  acid  has  but  a  very  slight  tendering  effect 
on  printed  cotton,  even  under  the  influence  of  steaming,  but  under  the  influence 
of  hot  dry  air  its  tendering  action  is  greater  than  that  of  oxalic  acid.  The  addition 
of  such  substances  as  glucose  appears  to  exert  a  protecting  influence  in  con- 
nection with  the  above  acids. 

t  The  destructive  action  of  these  acids  on  the  cotton  fibre  is,  perhaps,  not 
so  much  of  a  chemical  nature  as  mechanical,  it  being  caused  by  the  acids  crystal- 
lizing within  the  fibre  and  thus  breaking  the  cell-wall.  A  dry  heat,  for  instance, 
in  connection  with  these  acids  is  much  more  injurious  than  a  moist  heat,  a  fact 
which  is  of  much  importance  in  the  drying  of  cotton  prints,  where  the  above- 
mentioned  acids  may  have  been  used.  Scheurer  (Bull,  Soc.  Ind.  Mul.,  1900, 
August)  has  studied  the  action  of  lactic,  oxalic,  tartaric,  and  citric  acids  on  cotton, 
both  in  hot  air  and  in  steam.  The  result  of  his  investigations  showed:  (i)  Lactic 
acid  tenders  the  fabric  at  least  as  much  as  tartaric  and  citric  acids;  oxalic  acid 
being  the  most  energetic  in  this  respect;  (2)  the  tendering  takes  place  just  as 
much  before  steaming  as  after. 

t  Oxalic  acid  appears  to  have  a  peculiar  effect  on  cotton;  it  has  been  noticed 
that  if  a  piece  of  cotton  cloth  be  printed  with  a  thickened  solution  of  oxalic  acid, 
dried,  and  hung  in  a  cool  place  for  about  twelve  hours,  and  then  well  washed, 
the  printed  parts  exhibit  a  direct  affinity  toward  the  basic  dyes.  The  cotton 


294 


THE  TEXTILE  FIBRES 


12.  Action  of  Tannins. — Tannic  acid  unlike  other  acids, 
exhibits  quite  an  affinity  for  cotton,  the  latter  being  capable 
of  absorbing  as  much  as  7  to  10  per  cent  of  its  weight  of  tannic 
acid  from  an  aqueous  solution.*  Advantage  is  taken  of  this 
fact  in  the  mordanting  of  cotton  with  tannic  acid  and  tannins 
for  the  dyeing  and  printing  of  basic  colors,  f  Cotton  exhibits 

so  treated  does  not  become  greatly  tendered  or  otherwise  changed.  Toward 
substantive  dyes  it  exhibits  considerably  less  attraction  than  ordinary  cotton, 
while  with  alizarin  dyes  it  is  partially  reactive.  Tartaric  and  citric  acids  do  not 
produce  the  same  effect,  nor  does  the  neutral  or  acid  oxalate  of  potassium. 

*  According  to  Knecht  (Jour.  Soc.  Dyers1  &*  Col.,  1892,  p.  40)  tannic  acid  is 
absorbed  by  cotton  in  its  various  forms  as  follows: 


Form. 

Tannic  Acid 
Taken. 

Tannic  Acid 
Absorbed. 

Bleached  cotton  
Unbleached  cotton  

0.25  gram 
0.25     " 

0.0513  gram 
0.0563     " 

Mercerized  cotton  ....:.. 
Precipitated  cellulose.  .  .  . 

0.25     " 
0.25     " 

0.1033     " 
0-1525 

t  Though  tannic  acid  is  readily  taken  up  by  cotton,  gallic  acid  is  not  absorbed 
under  ordinary  conditions.  Gardner  and  Carter  (Jour.  Soc.  Dyers'  6*  Col.,  1898, 
p.  143)  give  the  relative  amounts  of  tannins  (and  similar  bodies)  absorbed  by 
cotton;  10  grams  of  cotton  were  soaked  for  three  hours  in  a  solution  containing 
i  gram  of  reagent  per  litre: 


Gallotannic  acid  ....................  .  ...........  32 

Catechutannic  acid  ..............................  32 

Gallic  acid  .....................................  o 

Pyrogallol  ......................  .....  '  ...........  45 

Phloroglucinol  .............................  >  ----  24 

Protocatechuic  acid  .............................  o 

Resorcinol  ...............  »  .....................  45 

Salicylic  acid  ......  .............................  o 

Guaiacol  .......................................  o 

Mendelic  acid  ..................................  7 

Pyrocatechol  ...........  ........................  o 

Koechlin  found  that  cotton  saturated  with  tannic  acid  in  a  solution  contain- 
ing 50  grams  per  litre  was  still  able  to  absorb  tannic  acid  from  a  solution  con- 
taining 20  grams  per  litre.  It  retained  the  whole  of  its  tannic  acid  in  a  solution 
containing  5  grams  per  litre,  and  only  began  to  lose  it  when  the  strength  was 
reduced  to  2  grams. 

The  effect  of  adding  other  acids  to  the  tannic  acid  solution  is  as  follows  (the 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     295 


a  similar  attraction  for  tungstic  acid;  the  expense  of  this  latter 
compound,  however,  precludes  its  adoption  as  a  mordanting 
agent. 

13.  Action  of  Alkalies.— Though  acids,  in  general,  have 
such  an  injurious  action  on  cotton,  alkalies,  on  the  other  hand, 
are  harmless  under  ordinary  conditions.  Dilute  solutions  of 
either  the  carbonated  or  caustic  alkalies,  even  at  a  boiling  tem- 
perature, if  air  is  excluded,  have  no  injurious  effect  on  cotton. 
In  the  presence  of  air  alkaline  solutions  cause  a  hydrolysis 
of  the  cellulose  in  a  manner  similar  to  acids,  with  the  result 
that  the  fibre  is  seriously  weakened.  The  prolonged  action  of 
alkalies  in  the  presence  of  air  is  an  important  one  to  bear  in  mind 
in  the  operations  of  bleaching,  dyeing,  or  mercerizing.*  Boil- 
ing solutions  of  dilute  alkalies  dissolve  or  emulsify  the  waxy 
and  fatty  impurities  encrusting  the  cotton  fibre,  hence  these 
reagents  are  largely  employed  in  the  scouring  of  cotton  goods.  | 

acids  being  present  in  quantities  equivalent  to  4.5  grams  of  acetic  acid  per  litre): 


Tannic  acid  alone  (as  above) 32 

+formic  acid 48 

"  -facetic  acid 48 

+propionic  acid 48 

+citric  acid 19 

' '  +tartaric  acid 20 

-f-sulphuric  acid 18 

+hydrochloric  acid 30 

1 '          +sodium  acetate 16 

*  The  absence  of  air  in  the  kier  boiling  of  cotton  goods  previous  to  bleaching 
is  a  very  important  factor.  The  presence  of  air  in  the  kier  with  the  caustic  alkali 
not  only  causes  oxidation  and  consequent  tendering  and  discoloration,  but  it 
also  tends  to  produce  air  bubbles  by  expansion  on  heating,  and  these  protect  the 
fibre  from  the  action  of  the  alkali. 

t  The  loss  of  weight  by  boiling  cotton  in  caustic  soda  solution  is  given  as 
follows 


Strength  of 
Solution. 

Loss  on  Boiling  for 

30  Minutes. 

i  Hour. 

i    per  cent 
2-5       " 

4.41  per  cent 
5-o8        " 

5.71  per  cent 
7-33        " 

296 


THE  TEXTILE   FIBRES 


The  action  of  alkaline  solutions  at  high  temperatures  (above 
ioo°_C.)  on  cotton  appears,  however,  to  be  a  destructive  one. 
Tauss  has  shown  that  if  cotton  be  digested  with  solutions  of 
caustic  soda  under  pressure,*  the  fibre  is  attacked  and  con- 
verted into  soluble  products;  the  degree  of  decomposition 
depending  on  the  pressure  and  the  strength  of  the  alkaline 
liquor,  in  accordance  with  the  following  table : 


Pressure. 

Strength  of  Alkali. 

3  Per  Cent  Na2O. 

8  Per  Cent  Na2O. 

Per  Cent  of  Cotton  Dissolved. 

i  atmosphere  
5  atmospheres 

12.  I 

15-4 
20.3 

22.  O 
58.0 
S9-o 

10                "                

Solutions  of  ammonia  do  not  act  on  cotton  until  quite  high 
temperatures  are  reached.  According  to  the  experiments  of 
L.  Vignon,  at  200°  C.  ammonia  reacts  with  cotton  cellulose, 
the  result  being  the  evident  formation  of  an  amino-cellulose 
compound,  the  product  evincing  a  greatly  increased  degree 
of  absorption  for  dyestuff  solutions,  especially  for  the 
acid  coloring  matters,  somewhat  after  the  manner  of  animal 
fibres,  f 

This  action  of  alkaline  solutions  on  cotton  under  high 
pressure  has  an  important  bearing  on  the  bleaching  of  this 
fibre,  where  it  is  subjected  to  such  action  by  boiling  with 
alkalies  in  pressure  kiers.J  This  phase  of  the  question  does 
not  appear  to  have  received  much  attention  from  either  the 
practical  bleacher  or  the  theoretical  chemist,  but  it  would 

*  Under  these  conditions  it  is  probable  that  a  hydration  of  the  cellulose  at 
first  takes  place,  followed  subsequently  by  a  hydrolysis. 

f  The  same  effect  is  said  to  be  obtained  when  cotton  is  treated  with  calcium 
chloride  and  ammonia  at  a  temperature  above  60°  C. 

J  The  presence  of  small  quantities  of  neutral  salts  (such  as  sodium  chloride, 
sodium  sulphate,  alumina,  calcium  sulphate,  iron,  etc.)  exert  a  distinctly  inhib- 
itory effect  on  the  action  of  caustic  soda  in  kier  boiling  of  cotton.  (See  Trotman, 
Jour.  Soc.  Chem.  Ind.,  1910,  p.  249.) 


CHEMICAL  PROPERTIES   OF  COTTON;    CELLULOSE     297 


seem  to  be  worthy  of  some  degree  of  intelligent  research  on 
the  part  of  both.* 

Concentrated  solutions  of  caustic  alkalies  have  a  peculiar 
effect  on  cotton;  the  fibre  swells  up,  becomes  cylindrical  and 
semi-transparent,  while  the  interior  canal  is  almost  entirely 
obliterated  by  the  swelling  of  the  cell-walls.  There  is  a  marked 
gain  in  weight  and  strength,  while  the  affinity  of  the  cotton  for 
coloring  matters  is  materially  increased.  This  effect  was  first 
noticed  by  John  Mercer  in  1844,  and  the  reaction  forms  the  basis 
of  the  modern  process  of  mercerizing,  under  which  title  a  more 
complete  and  extensive  discussion  of  this  reaction  will  be  found. 
Solutions  of  sodium  sulphide  appear  to  have  no  immediate 
tendering  action  on  cotton,  even  at  a  boiling  temperature.  If 
the  sodium  sulphide  is  dried  into  the  fibre  after  about  six  weeks, 
the  cotton  shows  a  loss  in  strength  of  from  10  to  20  per  cent. 
Also,  when  sodium  sulphide  is  dried  into  the  fibre  at  100°  C., 
the  tendering  amounts  to  from  10  to  20  per  cent.  Cotton 
containing  copper  sulphide  or  iron  sulphide  shows  no  appreciable 
amount  of  tendering.  When  cotton  is  impregnated  with 
sulphur  and  exposed  to  a  damp  atmosphere  for  several  weeks, 
its  tensile  strength  is  reduced  by  about  one-half.  This  is  per- 

*  Trotman  and  Pentecost  (Jour.  Soc.  Chem.  Ind.,  1910,  p.  4)  give  the  following 
analyses  of  cotton  properly  and  improperly  boiled-out  in  kiers: 


Properly  Boiled. 
Per  Cent. 

Improperly  Boiled. 
Per  Cent. 

Mineral  matter  

0.05-0.  75 

I  .OO 

Free  fat  
Fat  as  soap 

o.  10-0.15 
trace 

0.35-0.70 
o.  25-0.  <o 

Nitrogen  

0.05-0.10 

0.25-0.35 

The  relative  scouring  powers  of  different  alkalies  in  kier  boiling  is  also  given, 
the  loss  in  weight  of  the  cotton  being  taken  as  a  measure: 

Per  Cent  Loss. 

Caustic  potash 5 .  oo 

' '  soda 4 . 40 

Sodium  carbonate 3 . 70 

' '  borate 2 . 80 

' '  silicate 2 . 40 


298  THE  TEXTILE  FIBRES 

haps  due  to  the  oxidation  of  the  sulphur  into  sulphurous  and 
sulphuric  acids. 

If  cotton,  or  other  forms  of  cellulose,  be  treated  with  a 
concentrated  solution  of  caustic  soda  to  which  a  small  amount 
of  carbon  disulphide  has  been  added,  the  fibres  swell  up,  become 
disintegrated,  and  finally  form  a  gelatinous  mass.  This  latter 
is  soluble  in  a  large  amount  of  water,  producing  a  very  viscous 
solution,  technically  known  as  viscose.  From  this  solution 
hydrocellulose  may  be  precipitated  by  sulphurous  acid  gas,  as 
well  as  by  various  other  reagents.  Precipitation  also  occurs 
by  simply  allowing  the  solution  to  stand  for  some  time,  in  which 
case  the  hydra  ted  cellulose  separates  out  as  a  jelly-like  mass. 
Viscose  has  received  several  commercial  applications,  among 
which  may  be  mentioned  more  especially  the  use  of  its  solutions 
for  the  preparation  of  filaments  of  artificial  silk. 

Though  cotton  does  not  show  nearly  the  same  degree  of 
affinity  for  acids  and  alkalies  as  do  the  animal  fibres,  nevertheless 
it  has  been  shown  that  cotton  does  absorb  both  acids  and  alkalies 
from  their  solutions,  even  when  cold  and  dilute.  The  ratio  of 
absorption  appears  to  be  3  molecular  parts  of  acid  to  10  molec- 
ular parts  of  caustic  alkali.*  Vignon,  by  a  study  of  the 
thermochemical  reactions  of  cotton,  has  shown  that  when  this 
fibre  is  treated  with  acids  or  alkalies  a  liberation  of  heat  takes 
place, f  from  which  fact  it  would  appear  that  cotton  exhibits 
in  some  degree  the  properties  of  a  very  weak  acid  and  a  still 
weaker  base. 

14.  Action  of  Oxidizing  Agents.  Oxycellulose. — Strong 
oxidizing  agents,  such  as  chromic  acid,  permanganates,  chlorin, 
etc.,t  in  concentrated  solutions,  readily  attack  cotton,  convert- 

*  See  p.  271. 

t  Vignon  gives  the  following  results  in  calories  per  100  grams  of  cotton: 

KOH.        NaOH.         HC1.         HZSO4. 

Raw  cotton i .  30         i .  08        0.65        o .  60 

Bleached  cotton 2.27         2.20        0.65        0.58 

J  Scheurer  (Bull.  Soc.  Ind.  Mul.,  1900,  August)  has  studied  the  action  of 
ammonium  persulphate  on  cotton  when  steamed .  and  found  that  this  compound 
printed  in  the  proportion  of  5  to  10  grams  per  litre  of  gum  tragacanth  thickening, 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     299 

ing  it  into  oxycellulose.  This  substance  appears  to  possess 
an  increased  affinity  for  dyestuffs,  but  it  is  of  a  structureless 
and  brittle  nature,  hence  its  formation  greatly  tenders  the  fibre.* 
It  is  said  that  oxycellulose  is  indifferent  toward  the  tetrazo 
dyestuffs;f  and,  in  consequence,  these  may  be  employed  for 
the  purpose  of  detecting  the  presence  of  oxycellulose  in  cotton 
materials. 

Oxycellulose  appears  to  have  the  formula  CigH^eOie.  It 
dissolves  in  a  mixture  of  nitric  and  sulphuric  acids,  and  from 
the  low  number  of  hydroxyl  groups  reacting  with  the  nitric  acid, 
it  may  be  concluded  that  the  compound  is  both  a  condensed  as 
well  as  an  oxidized  derivative  of  cellulose.  Oxycellulose  is 
soluble  in  dilute  solutions  of  the  alkalies,  and  on  heating,  the 
solutions  develop  a  deep-yejlow  color.  When  warmed  with 
concentrated  sulphuric  a^cid  it  gives  a  pink  color  similar 
to  that  of  mucic  acid.  In  general  it  exhibits  a  close  resemblance 
to  the  pectic  group  of  colloidal  carbohydrates,  t  It  is  probable 
that  the  oxidation  products  of  cellulose  obtained  by  different 
means  do  not  all  give  the  same  oxycellulose,  or,  what  is  more 
probable,  the  oxy celluloses  which  have  so  far  been  studied  are 

tenders  the  fibre  to  the  e  :tent  of  10  per  cent.  If  used  in  a  strength  of  20  grams 
per  litre  the  tender'rg  amounts  to  40  per  cent. 

*  According  to  Yignon,  there  is  a  considerable  difference  in  the  heat  liberated 
by  the  action  of  caustic  soda  on  cellulose  and  oxycellulose,  as  follows: 

Cellulose o.  74  cals. 

Oxycellulose '. i .  30    " 

t  According  to  Vignon  (Bull.  Soc.  Chim.,  1898,  p.  917)  oxycellulose  may  be 
prepared  in  the  following  manner:  Cotton  is  first  purified  by  successive  treat- 
ment with  a  boiling  solution  of  i  per  cent  sodium  carbonate,  boiling  solution  of 
i  per  cent  potassium  hydrate,  cold  solution  of  i  per  cent  hydrochloric  acid,  and 
cold  solution  of  sodium  carbonate.  The  fibre  is  then  well  washed  with  water 
and  alcohol,  and  dried.  About  30  grams  of  this  purified  cotton  is  placed  in  a 
hot  solution  of  150  grams  of  potassium  chlorate  in  3000  c.c.  of  water,  and  125  c.c. 
of  hydrochloric  acid  is  gradually  added.  The  liquid  is  heated  for  one  hour,  then 
the  cotton  is  removed,  washed  with  water  and  alcohol  and  dried.  The  oxycellulose 
thus  obtained  is  in  the  form  of  short  brittle  fibres  which  turn  yellow  when  heated 
to  100°  C.  When  boiled  with  solutions  of  safranin  and  methylene  blue  a  gram 
absorbs  0.007  and  0.006  gram  respectively,  whereas  ordinary  cotton  absorbs 
o.ooi  and  0.002  gram  per  gram  of  dyestuff. 

J  See  Cross  and  Bevan,  Cellulose,  p.  56. 


300  THE  TEXTILE  FIBRES 

perhaps  mixtures  of  various  different  bodies  which  have  not  yet 
been  separated  and  isolated. 

The  oxidation  of  normal  cellulose  may  be  effected  in  either 
acid  or  alkaline  liquors,  and  according  to  the  oxidizing  agent 
employed  and  the  method  of  operation,  a  number  of  different 
oxy celluloses  may  be  produced.  All  of  them,  however, 
possess  an  affinity  for  basic  dyes  and  yield  furfural  when  dis- 
tilled with  hydrochloric  acid.  The  quantity  of  furfural  obtained 
serves  as  a  measure  of  the  amount  of  oxygen  contained  in  the 
cellulose  in  excess  of  that  required  to  satisfy  the  formula  of 
normal  cellulose  (CeHioOs). 

Like  hydrocellulose,  oxycellulose  has  a  strong  affinity  for 
water  and  is  easily  hydrated. 

Oxycellulose  may  be  distinguished  from  hydrocellulose  by 
its  reaction  with  Nessler's  reagent,  with  which  it  forms  a  dark 
gray  precipitate. 

|C-'  As  indicated  by  its  reactions  it  is  probable  that  oxycellulose 
is  characterized  by  the  presence  in  the  molecule  of  carbonyl 
(CO)  and  methoxy  (OCH3)  groups. 

While  pure  cellulose  has  but  a  slight  reducing  action  on 
Fehling's  solution,  oxycellulose  like  hydrocellulose  causes  a 
considerable  reduction;  the  reaction  being  so  well  denned 
that  it  may  be  employed  as  a  test  to  determine  the  presence 
of  oxycellulose  in  cotton  that  has  been  overbleached.* 

*  Schwalbe  and  Robinoff  (Zeit.  angew.  chem.,  1911,  p.  256)  have  shown  that 
cellulose  which  has  been  chemically  affected  by  bleaching  undergoes  hydrolysis 
when  heated  with  water  to  high  temperatures.  It  was  found  that  in  bleaching 
cotton  with  hypochlorite  solutions  followed  by  souring  with  hydrochloric  acid, 
the  formation  of  oxycellulose  is  promoted  by  the  use  of  low  strengths  of  acid. 
In  addition  to  determinations  of  the  solubility  of  the  cellulose  in  dilute  caustic 
soda  the  so-called  "mucilage  values"  (the  weight  of  the  flocculent  matter  pre- 
cipitated by  alcohol  after  neutralization  of  the  alkaline  extract)  were  also  ascer- 
tained. Above  150°  C.  the  mucilage  value  was  much  larger  and  consequently 
this  temperature  is  stated  as  the  "critical  temperature"  for  cotton  cellulose. 
A  determination  of  the  copper  value  of  cotton  treated  with  hot  caustic  soda 
solution  shows  that  a  concentration  of  4  per  cent  of  alkali  in  the  case  of  cold  lyes 
was  the  most  destructive.  The  products  of  hydrolysis  formed  by  the  action 
of  i  to  2  per  cent  sodium  hydroxide  solutions  appeared  to  undergo  decomposi- 
tion above  100°  C.  there  being  a  decrease  in  the  copper  value.  The  decrease 
in  the  hydrolysis  affected  by  lyes  of  5  per  cent  strength  and  over  is  probably 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     301 

A  method  of  determining  the  amount  of  copper  reduced  in  the 
Fehling's  solution  has  been  devised  by  Schwalbe.*  About  3 
grams  of  air-dried  cotton  are  boiled  for  fifteen  minutes  under  a 
reflux  condenser  with  100  cc.  of  Fehling's  solution  and  200 
cc.  of  water,  the  flask  being  constantly  shaken.  The  hot 
liquid  is  then  filtered,  the  residue  washed  with  boiling  water, 
and  heated  on  the  water-bath  for  fifteen  minutes  with  30  cc. 
of  6.5  per  cent  nitric  acid,  and  the  dissolved  copper  is  finally 
determined,  preferably  by  the  electrolytic  method.  By  this 
means  the  following  so-called  "  copper  values  "  were  obtained: 

Surgical  cotton  wool 1.6-1.8 

Bleached  mercerized  yarn i .  6-1 . 9 

Artificial  silk  (Glanzstoff) i .  i 

Hydrocellulose 5 . 2-5 . 8 

Parchment  paper 4.2 

Bleached  sulphite  wood  pulp 3.9 

Over-bleached  wood  pulp 19.3 

Oxycellulose  (bleaching  powder  on  filter-paper) 7.9 

Bleached  cotton  rag 6.5 

Cellulose  Peroxide. — Cotton  and  linen  fabrics  which  have 
been  bleached  and  acidified,  without  the  subsequent  use  of  an 
antichlor,  sometimes  retain  the  property  characteristic  of 
"  active  oxygen  "  by  liberating  iodin  from  potassium  iodide 
for  a  much  longer  time  than  is  consistent  with  the  survival  of 
traces  of  residual  hypochlorities.  Cross  and  Bevanf  call  atten- 
tion to  a  case  where  cotton  cloth  was  bleached,  soured,  and 
washed  under  normal  conditions,  and  yet  retained  an  acid 
reaction  and  oxidizing  properties  toward  potassium  iodide 
even  after  exhaustive  washing  with  distilled  water.  The 
oxidizing  property  was  rapidly  destroyed  by  boiling  with 
water  or  by  treatment  with  "  antichlor."  Cross  and  Bevan 
assume  this  character  to  be  due  to  the  formation  of  cellulose 
peroxide.  DitzJ  has  observed  that  the  same  phenomenon  can 

due  to  the  beginning  of  mercerization  or  hydration.  In  this  case  American  cotton 
gives  a  much  higher  copper  value  than  Egyptian  cotton. 

*  See  Berichte,  1907,  pp.  1347  and  4523. 

f  Z$it.  angew.  chem.,  1906,  p.  2101. 

t  Chem  Zeit.,  1907,  p.  833. 


302  THE  TEXTILE  FIBRES 

be  produced  by  gradually  heating  cotton  with  an  acid  solution 
of  ammonium  persulphate  up  to  a  temperature  of  80°  C. 

15.  Action  of  Metallic  Salts. — In  its  action  toward  various 
metallic  salts  cotton  is  very  neutral,  thereby  differing  con- 
siderably from  both  wool  and  silk.*  If  the  salts,  however, 
are  present  in  a  very  basic  condition,  cotton  is  capable  of  decom- 
posing them  and  loosely  fixing  the  metallic  hydroxide,  f  When 
cotton,  for  instance,  is  digested  with  a  solution  of  barium 
hydrate,  or  with  the  basic  salts  of  such  metals  as  lead,  zinc, 
copper,  tin,  aluminium,  iron,  chromium,  cobalt,  nickel,  man- 
ganese, molybdenum,  tungsten,  etc.,  the  fibre  absorbs  an 
appreciable  quantity  of  the  basic  oxide  though  very  much  less 
than  is  the  case  with  the  animal  fibres.  Salts  of  stannic  acid 
(sodium  stannate)  are  also  absorbed  by  cotton  to  quite  a  marked 
degree.  In  this  instance,  stannic  acid  appears  to  act  much 
in  the  same  manner  as  tannic  acid.  Many  salts,  especially 
those  of  an  acid  nature,  will  tender  the  cotton  fibre,  probably 
due  to  the  liberation  and  drying-in  of  the  acid.  Consequently, 
such  salts  should  be  avoided  or  used  very  carefully  with  cotton, 
and  any  excess  should  be  thoroughly  eliminated  by  subsequent 
washing  before  the  material  dries.  Magnesium  chloride  is 
largely  used  in  the  preparation  of  finishes  for  cotton  goods, 

*  Michaelis  (Beitrage  zur  Theorie  des  Farbeprocesses,  die  Farbungseigenschaften 
der  Cellulose;  Pfluger's  Arch,  ges.  Physiol.,  97,  pp.  634-640)  states  that  cotton  has 
the  property  of  precipitating,  by  mechanical  surface  attraction,  mordants  such 
as  salts  of  aluminium,  iron,  chromium,  zinc,  with  weak  acids,  which  on  treat- 
ment in  the  dyeing  vat  form  between  the  molecules  of  the  fibre  insoluble  com- 
pounds with  the  dyestuffs. 

t  Liechti  and  Suida  (Jour.  Soc.  Chem.  Ind.,  1883,  p.  537)  show  the  influence 
of  the  basicity  of  aluminium  salts  on  their  absorption  by  cotton.  Solutions 
containing  200  grams  per  litre  of  the  respective  sulphates  were  used,  as  follows: 

Composition  of  Sulphate.  ^Absorbed*'0' 

Al2(SO4)r  i8H2O  (normal) 12.9 

A1(S04)  •  (OH)  6 51.0 

AU(S04)3-(OH)4 58.7 

A12(SO,)-(OH)4 — 

The  last  dissociated  too  rapidly  for  experimentation.  The  fact  that  a  salt 
is  a  basic  one  is  not  any  indication  that  it  will  act  as  a  mordant;  the  basic  chlorides 
and  oxychlorides  of  aluminium  are  not  mordants. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE     303 

and  tendering  of  the  fibre  may  occur  if  fabrics  containing  this 
salt  are  subjected  to  high  temperatures  such  as  experienced  in 
drying  over  hot  rolls.* 

'  16.  Flame-proofing  of  Cotton  Fabrics.  The  rather  highly 
inflammable  nature  of  cotton  fabrics  as  compared  with  woolen 
has  frequently  been  an  obstacle  to  their  use  for  many  purposes. 
Cotton  garments  made  from  napped  or  fleeced  cotton  cloth 
such  as  flannelette  has  often  been  the  cause  of  severe  accidents 
owing  to  its  inflammable  nature.  The  same  is  true  of  the  use 
of  cotton  for  theatrical  costumes  and  hangings,  lace  curtains, 
etc.  It  has  been  found  possible  to  reduce  greatly  the  inflammable 
nature  of  cotton  by  treatment  of  the  fibre  with  various  metallic 
salts.  Compounds  of  ammonium  t  have  been  largely  employed 
for  this  purpose.  The  volatility  of  these  compounds  when 
subjected  to  a  high  temperature  causes  a  layer  of  inert  gas  to 
form  around  the  fibre,  and  thus  prevents  it  from  flaming.  Alum 

*  The  following  facts  have  been  determined  with  reference   to  the  use  of 
magnesium  chloride  on  cotton  goods: 

(1)  An  aqueous  solution  of  magnesium  chloride  does  not  begin  to  decom- 
pose until  a  temperature  of  223°  F.  is  reached,  neither  alone  nor  in  the  presence 
of  an  excess  of  air,  nor  in  steam,  nor  in  the  presence  of  cellulose,  nor  in  admix- 
ture with  other  ordinary  finishing  agents. 

(2)  The  amount  of  hydrochloric  acid  generated  up  to  a  temperature  of  480°  F. 
is  quite  small,  aggregating  only  about  2  per  cent  of  the  whole. 

(3)  The  deterioration  of  cotton  finished  with  magnesium  chloride  does  not 
take  place  below  223°  F.     Such  cotton  may  therefore  be  safely  treated  with 
steam  at  the  atmospheric  pressure. 

(4)  Cotton  finished  with  magnesium  chloride  should  not  be  subjected  to  high 
temperatures,  especially  such  treatment  should  not  be  prolonged.     The  limiting 
temperature  for  the  drying  of  such  material  should  be  212°  F. 

(5)  If  a  temperature  of  212°  F.  in  drying  is  not  exceeded,  magnesium  chloride 
may  be  employed  without  danger  in  the  finishing  of  cotton  fabrics.     It  should 
not  be  used,  however,  if  such  material  is  to  be  subjected  to  steam  under  pressure 
or  to  ironing. 

f  A  solution  highly  recommended  for  this  purpose  is  composed  of: 

3  parts  ammonium  phosphate, 
2     "  chloride, 

2     ' '  sulphate, 

40     ' '      water. 

The  cloth  may  either  be  impregnated  with  this  solution  or  the  starch  size 
may  be  made  up  with  it. 


304  THE  TEXTILE  FIBRES 

mixed  with  the  sizing  of  cotton  goods  also  materially  reduces 
their  liability  to  catch  fire.  Borax  and  sodium  tungstate  have 
also  been  extensively  employed  for  the  same  purpose.  All 
of  these  salts,  however,  have  the  bad  defect  of  being  very  soluble, 
consequently  the  non-inflammable  property  they  give  to  the 
cotton  is  removed  when  the  material  is  washed. 

Perkin  has  found  that  a  permanent  treatment  may  be  given 
the  cotton  by  impregnating  the  cloth  with  a  solution  of  sodium 
stannate  (45°  Tw.),  squeezing,  drying  over  hot  rolls,  and  then 
treating  with  a  solution  of  ammonium  sulphate  (15°  Tw.). 
The  fabric  is  then  dried  a  second  time  and  then  washed  to 
remove  the  sodium  sulphate  formed  in  the  reaction,  leaving  in 
the  fibre  precipitated  stannic  oxide.*  This  treatment  makes 
the  fabric  quite  non-inflammable,  and  this  property  is  permanent 
against  repeated  washings.  It  also  leaves  the  fibre  soft  to  the 
feel  and  does  not  reduce  its  tensile  strength. 

17.  Action  of  Coloring  Matters. — In  its  behavior  toward 
coloring  matters  cotton  differs  most  markedly  from  the  animal 
fibres.  Of  the  natural  dyestuffs,  only  a  few  color  the  cotton 
fibre  without  a  mordant;  with  the  coal-tar  colors,  cotton 
exhibits  no  affinity  for  most  of  the  acid  or  basic  dyes,  and  these 
can  only  be  applied  on  a  suitable  mordant.  The  substantive 
colors,  however,  are  readily  dyed  on  cotton,  in  a  direct  manner, 
and  since  their  introduction  the  methods  of  cotton  dyeing  have 
been  practically  revolutionized. 

There  has  been  much  discussion  as  to  whether  the  phenomena 
of  dyeing  with  reference  to  cotton  are  of  a  physical  or  chemical 
nature,  f  Unlike  the  animal  fibres,  cotton  does  not  possess 
groups  of  a  very  distinctly  active  chemical  nature;  that  is 
to  say,  it  cannot  be  said  to  noticeably  exhibit  either  acid  or 
basic  properties.  The  only  groups  in  cotton  cellulose  which 
may  be  considered  chemically  active  are  the  hydroxyl  groups. 

"This  is  known  as  the  "Non-Flam"  process  and  is  the  subject  of  a  number 
of  patents. 

f  From  the  view-point  of  colloidal  chemistry  it  would  seem  that  the  process 
of  dyeing  is  one  of  adsorption,  and  the  principal  force  operating  is  capillary  action. 
(See  Rosenthal.  Bull.  Soc.  Chem.,  1911,  pp.  12  and  224.) 


CHEMICAL  PROPERTIES  OF  COTTON;  CELLULOSE  305 

These  can  be  rendered  inactive  by  acetylation,  and  it  has  been 
shown  *  that  cotton  so  treated  does  not  exhibit  any  difference 
in  dyeing  properties  from  ordinary  cotton,  and  this  leads  us 
to  the  assumption  that  in  the  case  of  cotton,  the  phenomena 
of  dyeing  rest  on  a  physical  dissociation  of  the  dyestuff  mole- 
cule determined  by  the  fibre;  that  is  to  say,  the  process  of 
dyeing  with  reference  to  cotton  must  be  attributed  (in  great 
measure  at  least)  to  the  action  of  dissociation,  dissolution, 
and  capillarity  ;f  in  other  words,  to  purely  physical  or  physico- 
chemical  causes;  and  purely  chemical  reactions,  if  they  come 
into  play  at  all,  are  of  secondary  importance. 

Minajeff  {  by  comparing  the  action  of  dyestuffs  on  artificial 
silk  and  cotton  concludes  with  reference  to  the  latter  that  (a) 
the  cuticle  of  the  bleached  fibre  has  no  influence  on  the  dyeing 
process,  (b)  the  lamellar  structure  of  cotton  plays  no  part  in 
differentiating  its  dyeing  action  from  that  of  artificial  silkr 
and  (c)  the  canal  in  the  cotton  fibre  plays  no  important  role, 
mordants  and  color-lobes  being  deposited  within  the  canal  to 


*  Suida,  Farber-Zeit.,  1905. 

t  Kuhn  (Die  Baumtvolle,  p.  183)  finds  there  is  a  greater  deposition  of  coloring 
matter  along  the  lumen  of  the  fibre  according  as  the  dyeing  process  is  more 
complete,  although  even  in  the  best  dyed  fibres  the  largest  proportion  of  dyestuff 
is  deposited  on  the  outer  surface.  De  Mosenthal  has  pointed  out  that  a  single 
fibre  does  not  absorb  coloring  matter  by  capillary  attraction,  but  the  dyestuff 
solution  apparently  rises  between  the  fibres  and  passes  into  them  through  the 
pores  in  the  cell- wall.  Crum  believed  that  the  coloring  matter  was  deposited 
within  the  central  canal  or  lumen;  but  O'Neill  showed  that  this  was  seldom  the 
case,  the  whole  cell- wall  being  colored  in  a  uniform  manner.  According  to 
Georgievics  a  porous  structure  of  the  cotton  fibre  could  hardly  be  considered 
essential  to  its  dyeing,  for  fibres  not  possessing  any  organic  structure  at  all  (such 
as  the  various  forms  of  artificial  silk)  can  be  dyed  in  practically  the  same  manner 
as  cotton.  Recent  work  by  Haller  has  shown  that  cotton  dyed  with  chrome 
yellow  when  examined  in  cross-section  even  under  a  magnification  of  1000  diam- 
eters, failed  to  exhibit  any  trace  of  porous  structure.  The  cell-walls  were  homo- 
geneously impregnated  with  the  color  in  a  very  fine  state  of  division.  Haller 
has  shown  also  that  cotton  fibres  still  attached  to  the  seed-shell  dye  as  satis- 
factorily as  ordinary  cotton  fibres.  In  this  case  both  ends  of  the  fibre  are  closed, 
and  the  central  canal  is  not  exposed  to  the  capillarity  of  color  solutions;  hence 
it  is  to  be  concluded  that  the  central  canal  in  the  cotton  fibre  does  not  play  any 
important  part  in  the  dyeing  process. 

+  Zeit.  Fdrb.  Ind.;  1909,  p.  236. 


306  THE  TEXTILE  FIBRES 

only  a  very  limited  extent.  The  determining  factors  appear  to 
be  thickness,  density,  and  capillarity,  rather  than  microscopic 
structure. 

18.  Action  of  Ferments. — Though  resistant  to  the  action 
of  moths  and  insects  in  general,  cotton  is  liable  to  undergo 
fermentation  as  is  evidenced  by  the  formation  of  mildew  on 
cotton  fabrics  stored  in  damp  places.  Though  this  fermenta- 
tion is  often  induced  by  the  presence  of  more  or  less  starchy 
matter  contained  in  the  sizing  materials  used  in  finishing  the 
goods,  yet  pure  cellulose  itself  can  also  be  fermented,  and 
Omeliansky  has  succeeded  in  isolating  the  particular  bacillus 
which  destroys  cellulose. 

According  to  Knecht,*  human  saliva  has  a  peculiar  and 
distinct  effect  on  cotton.  His  experiments  show  that  a  piece 
of  bleached  calico,  saturated  with  saliva,  will  absorb  considerably 
more  dyestuff  on  dyeing  with  substantive  colors  than  untreated 
cotton.  This  is  not  due  to  mucus,  or  to  any  of  the  salts  con- 
tained in  the  saliva,  but  probably  to  the  enzyme  ptyalin,  since 
the  saliva  loses  the  power  of  producing  the  effect  after  boiling. 
Of  other  enzymes,  diastase  was  also  found  to  have  some  action, 
though  very  slight.  This  action  of  saliva  on  cotton  may  explain 
some  faults  arising  in  dyeing  cotton  pieces. 

Mildew  does  not  appear  as  often  on  white  and  colored  as 
on  gray  (unbleached)  cloth,  which,  being  sized,  is  much  more 
liable  to  this  defect.  The  essential  conditions  for  the  produc- 
tion of  mildew  appear  to  be  (i)  dampness,  (2)  lack  of  fresh 
air,  (3)  the  presence  of  certain  bodies  (such  as  flour,  etc.)  suitable 
as  foods  for  the  fungi.  The  more  common  varieties  of  mildew 
are: 

(i)  Green  mildew,  a  common  form  generally  due  to  Pen- 
icillium  glaucum  and  Aspergillus  glaucus,  which  are  closely 
allied,  but  which  are  distinguishable  from  the  way  in  which 
the  spores  are  attached.  In  the  former  the  spores  are  on 
branches,  while  in  the  latter  they  are  attached  to  the  head; 
they  grow  rapidly  and  generally  form  rather  large  patches. 

*  Jour.  Soc.  Dyers1  6*  Col.,  1905,  p.  189. 


CHEMICAL  PROPERTIES  OF  COTTON;    CELLULOSE      307 

(2)  Brown  mildew  is  frequently  found  on  cloth,  and  is  due 
to  various  species  of  fungi,  of  which  Puccinia  graminis  is  perhaps 
the   most   common.     This   and  the  brick-red   mildew  noticed 
below  are  frequently  mistaken  for  iron  stains,  the  color  of  which 
they  closely  resemble.     They  are  easily  distinguished  by  the 
manner  in  which  they  occur  in  small  spots,  often  of  a  ring  shape, 
and  they  do  not  give  the  Prussian-blue  test. 

(3)  Brick-red  mildew  is  not  very  frequent  and  the  fungus 
which  causes  it  has  not  been  definitely  recognized;    it  grows 
rapidly  at  first,  but  has  no  great  vitality  and  after  a  time  the 
development  stops. 

(4)  Yellow  mildew,   a  common  variety  occurring  in  large 
irregular  patches  and  spots.     Not  requiring  much  air  for  its 
development,  it  extends  much  more  into  the  folds  of  the  cloth 
than  do  most  of  the  other  kinds.     It  is  a  yellow  variety  of 
the  Aspergillus  glaucus  (Eurotium)  and  may  also  be  Oidium 
aurantiacum. 

(5)  Black  mildew,  due  often  to  fungi  belonging  to  the  genus 
Tilletia,  is  occasionally  found;   it  is  very  rapid  in  growth. 

(6)  Purple  mildew  is  rare. 

(7)  Bright  pink  mildew  is  also  rare. 


CHAPTER  XIII 
MERCERIZED   COTTON 

i.  Mercerizing  is  a  term  applied  to  that  process  whereby 
cotton  is  treated  with  concentrated  caustic  alkalies.  In  its 
strictest  significance,  however,  it  refers  most  directly  to  the 
process  of  giving  cotton  a  high  degree  of  lustre  by  subjecting 
it  simultaneously  to  the  chemical  action  of  caustic  alkalies  and 
the  mechanical  action  of  tension  sufficient  to  prevent  contraction. 
The  process  is  named  from  John  Mercer,*  who  first  discovered 

*  Mercer  took  out  a  patent  for  the  process  in  1850,  and  he  practically  describes 
therein  all  the  conditions  of  mercerizing  with  the  exception  of  that  of  tension. 
Mercer  only  employed  the  process  for  increasing  the  solidity  and  strength  of 
cotton  fabrics — not  employing  tension  he  did  not  notice  very  closely  the  increased 
lustre.  Persoz  in  his  Traiti  de  I' Impress  ion  (1846)  describes  a  method  of  dyeing 
manganese  bronze  in  France  in  which  caustic  soda  lye  of  35°  Be.  was  employed, 
and  mentions  that  this  strength  was  considered  necessary  to  produce  shrinkage 
of  the  fabric.  The  action  of  caustic  soda  on  cotton,  therefore,  as  far  as  contraction 
is  concerned,  seems  to  have  been  known  before  Mercer's  discovery  was  patented. 
Gamier  and  Depoully  in  1883  employed  the  process  for  producing  crepe  by  using 
caustic  soda  solutions  to  shrink  the  fabric  in  places.  Lowe  in  1890  took  out  an 
English  patent  describing  the  use  of  tension  during  mercerization  to  produce  a 
lustre.  The  combination  of  Mercer's  and  Lowe's  patents  describe  in  detail 
all  the  necessary  conditions  for  mercerizing  as  practised  at  the  present  time. 
The  process  of  mercerizing  has  been  subject  to  a  great  number  of  patents,  espe- 
cially by  Thomas  and  Prevost  of  Germany.  This  resulted  in  considerable 
litigation  in  many  countries.  As  far  as  the  actual  chemical  process  itself  is  con- 
cerned, however,  there  does  not  appear  to  have  been  any  material  advance 
beyond  the  facts  first  discovered  by  Mercer  and  patented  by  him  in  1850;  with 
regard  to  the  element  of  carrying  out  the  process  under  tension,  it  may  be  said 
that  this  was  first  described  and  patented  by  Arthur  Lowe  in  1890,  and  this 
included  the  application  of  tension  either  during  or  after  the  treatment  with  caustic 
alkali.  Lowe's  object  in  stretching  the  material,  however,  was  primarily  to 
prevent  the  loss  encountered  by  the  shrinkage  of  the  goods,  though  he  does  also 
make  a  specific  statement  that  the  cotton  acquires  an  increased  lustre  and  finish  by 

308 


MERCERIZED  COTTON  309 

the  effect  of  strong  solutions  of  caustic  alkalies  on  cotton  in  the 
year  1844.  It  was  not  until  the  last  decade,  however,  that  the 
process  attained  any  degree  of  commercial  success;  but  during 
the  last  few  years  it  has  given  practically  a  new  fibre  to  the 
textile  industry. 

Mercerizing,  in  its  essential  meaning,  relates  to  the  action  of 
certain  chemicals  on  cellulose,  whereby  the  latter  is  changed  to 
a  product  known  as  cellulose  hydrate,  though,  technically,  the 
term  has  come  to  mean  the  process  concerned  with  the  impart- 
ing of  a  silk-like  lustre  to  the  fibre.  As  generally  understood, 
it  consists  briefly  in  impregnating  cotton  yarn  or  cloth  with  a 
rather  concentrated  cold  solution  of  caustic  soda  and  sub- 
sequently washing  out  the  caustic  liquor  with  water,  the  material 
being  either  held  in  a  state  of  tension  during  the  time  it  is  treated 
with  the  caustic  alkali  in  order  to  prevent  contraction,  or 
stretched  back  to  its  original  length  after  treatment  with  the 
alkali,  but  previous  to  washing.  In  either  case,  the  material 
must  be  in  a  state  of  tension  during  the  process  of  washing. 
There  are  two  separate  phases  of  the  mercerizing  process  repre- 
sented in  the  above  operations  which  must  be  separately  under- 
stood in  order  to  comprehend  the  exact  nature  of  the  change 
which  takes  place  in  the  appearance  of  the  fibre;  the  one  is  the 
chemical  action  of  the  caustic  soda,  and  the  other  is  the  mechan- 
ical effect  brought  about  by  the  tension.  The  action  of  the 
caustic  alkali  is  to  effect  a  chemical  transformation  in  the  sub- 
stance of  the  fibre,  a  further  chemical  reaction  taking  place 
when  this  product  is  treated  with  water. 

2.  Alkali-cellulose. — As  previously  pointed  out  (p.  278), 
cellulose  has  the  property  of  combining  with  caustic  soda  in 
the  ratio  of  Ci2H2oOio:  NaOH  to  form  a  product  known  as 

the  process.  The  only  novelty  put  forward  by  Thomas  and  Prevost  was  the  use 
of  a  particular  kind  of  cotton,  that  is,  long-stapled  varieties;  but  as  both  Mercer's 
and  Lowe's  patents  claim  the  use  of  all  varieties  of  cotton,  it  was  difficult  to  see 
on  what  ground  Thomas  and  Prevost  could  substantiate  their  claim  for  a  patent. 
Patents  covering  the  process  of  mercerizing  appear  to  be  without  foundation; 
though  for  machinery  and  appliances  for  carrying  out  the  same  such  patents 
may  be  perfectly  legitimate.  Decisions  on  this  matter  in  the  United  States  and 
Germany  have  invalidated  Thomas  and  Prevost's  patents. 


310  THE  TEXTILE  FIBRE? 

alkali-cellulose,*  Ci2H2oOio-NaOH.  The  formation  of  this 
compound  does  not  appear  to  disintegrate  the  organic  structure 
of  the  fibre-cell,  provided  the  proper  conditions  are  maintained. 
The  alkali-cellulose,  however,  is  apparently  a  rather  feebly 
combined  molecular  aggregate,  and  does  not  exhibit  much 
stability  toward  reagents  in  general,  t  It  is  even  decomposed 
by  the  action  of  water,  the  effect  of  the  latter  being  to  disrupt 
the  bond  of  molecular  union  between  the  alkali  and  cellulose, 
with  the  consequent  re-formation  of  caustic  soda  and  the 
introduction  of  water  into  the  cellulose  molecule.  {  This  latter 
substance,  which  may  be  termed  cellulose  hydrate,  forms  the 
chemical  basis  of  'mercerized  cotton.  The  theory  that  caustic 
soda  effects  a  true  chemical  combination  with  cellulose  is  some- 
what supported  by  the  fact  that  mercerized  cotton  undergoes 
chemical  changes  to  which  ordinary  cotton  is  not  susceptible. 
For  instance,  the  former  is  much  more  readily  dissolved  by  a 
solution  of  ammoniacal  copper  oxide;  it  is  chemically  reactive 
with  carbon  disulphide  with  the  formation  of  soluble  cellulose 
thiocarbonates  ;  alkali-cellulose  also  reacts  with  benzoyl  chloride 
and  acetic  anhydride,  giving  rise  to  cellulose  benzoates  and 
acetates.  The  nature  of  the  chemical  change  in  mercerized 

*  According  to  Schwalbe  (Berichte,  1907,  p.  3876)  the  absorption  curve  of 
cotton  with  caustic  soda  shows  two  distinct  points  corresponding  respectively 
to  molecular  ratios  of 


:  NaOH 

and  Ci2H20Oio  :  2NaOH. 

Schwalbe  ascribes  to  alkali-cellulose  the  formula,  Ci2Hi9OioNa,  claiming  it  is  a 
definite  chemical  compound  capable  of  combining  with  more  alkali  until  eventually 
the  compound  C]2Hi9OioNa  •  NaOH  is  formed. 

t  Alkali-cellulose  is  decomposed  on  exposure  to  the  air  by  reason  of  the 
moisture  and  carbon  dioxide  combining  with  the  alkali.  Alkali-cellulose  freed 
from  soda  by  washing  with  water,  that  is  to  say,  converted  into  hydrocellulose, 
has  a  greater  affinity  for  substantive  dyes  than  the  alkali-cellulose  washed  with 
hot  absolute  alcohol.  In  the  latter  case  there  is  no  hydration  of  the  cellulose. 
(Miller,  Berichte,  1910,  p.  3430.) 

J  Washing  with  absolute  alcohol  (cold)  does  not  decompose  the  alkali-cellulose, 
and  thus  allows  of  the  determination  of  the  quantity  of  soda  fixed  or  combined 
with  the  cellulose  in  the  case  of  treatment  with  caustic  soda  solutions  of  different 
degrees  of  concentration.  Hot  alcohol,  however,  decomposes  the  alkali-cellulose. 


MERCERIZED   COTTON 


311 


cotton,  however,  is  rather  ill  defined  ;*  it  no  doubt  can  be  included 
under  that  class  of  reactions  which  stands  somewhat  midway 
between  ordinary  physical  and  chemical  changes,  and  is  to  be 

*  Vieweg  (Berichte,  1907,  p.  3876)  has  studied  the  absorption  of  caustic  soda 
by  cotton  in  the  following  manner:  3  grams  of  pure  absorbent  cotton,  dried 
at  212°  F.  were  immersed  in  200  c.c.  of  caustic  soda  solutions  of  different  degrees 
of  concentration.  After  two  hours  standing,  50  c.c.  of  the  liquor  in  each  test 
was  taken  out  and  titrated  with  N/io  sulphuric  acid,  using  phenolphthalein  as 
an  indicator.  The  loss  in  strength  of  the  soda  solution* allowed  a  calculation  to 
be  made  as  to  the  amount  of  caustic  soda  combined  with  the  cotton.  The 
following  table  gives  the  results  obtained: 


Concentration  of  caustic 

soda;     grams     NaOH 

per   100  c.c.  water.  .  . 

0.4 

2.O 

6.0 

8.0 

12 

16 

20 

24 

28 

33 

35 

40 

Caustic    soda     fixed; 

grams  NaOH  per  100 

• 

grams  cotton  

0.4 

0.9 

2.7 

4-4 

8.4 

12.6 

13 

13 

IS-4 

20.4 

22.5 

22.5 

It  will  be  noted  that  there  are  two  points  where  the  absorption  becomes 
constant,  at  a  concentration  of  about  16  per  cent  NaOH,  and  again  at  35  per 
cent  NaOH.  The  absorption  in  each  case  would  apparently  correspond  to  alkali- 
cellulose  compounds  of  (C6HioO6)2-NaOH,  and  (C6HioO5)2-2NaOH,  respectively. 

Hiibner  and  Teltscher  (Jour.  Soc.  Chem.  Ind.,  1909,  p.  641)  have  also  studied 
this  question  in  a  somewhat  different  manner:  10  grams  of  purified  cotton  were 
immersed  in  600  c.c.  of  caustic  soda  solutions  of  different  concentrations  for 
sixty-seven  hours.  The  excess  of  caustic  soda  was  then  drained  off  and  the 
samples  were  washed  with  absolute  alcohol  (cold)  until  no  longer  showing  an  alkaline 
test  with  phenolphthalein.  The  amount  of  combined  caustic  soda  was  then 
determined  by  ignitions.  The  results  are  shown  in  the  following  table: 


Grams  of  NaOH  in 
100  c.c.  of  Liquor. 

°Tw. 

NaOH  Retained  by 
100  grams  Cotton. 
Grams. 

Times  Washed  with 
Absolute  Alcohol. 

0.4 

I 

o.  190 

6 

2-3 

5 

0.198 

13 

4.19 

10 

0.330 

17 

8.68 

20 

o.  710 

30 

9.98 

23 

1-456 

38 

11.47 

26 

2.752 

45 

J3-39 

3° 

3-250 

63 

15-47 

35 

3-298 

70 

17.67 

40 

3.600 

74 

20.03 

45 

3-184 

81 

22.42 

5° 

2.  722 

86 

27.10 

60 

2.824 

89 

31-74 

70 

3-030 

Qi 

36.54 

80 

3.024 

06 

312  THE  TEXTILE  FIBRES 

particularly  observed  in  connection  with  those  bodies  possessing 
a  high  degree  of  molecular  complexity,  such  as  various  colloidal 
substances  and  the  large  number  of  naturally  occurring  car- 
bohydrates, starches,  gums,  etc.  The  fact  that  there  is  no 
evidence  of  disorganization  in  the  fibre  cell,  as  may  be  observed 
from  its  physical  properties  and  microscopic  appearance,  is  a 
strong  argument  against  true  chemical  change,  which  would 
necessitate  a  rearrangement  in  the  atomic  grouping  in  the 
substance  of  the  fibre.*  This  would  result  in  a  decomposition 
of  its  organized  structure,  which  would  at  once  be  manifested  in  a 
decrease  in  the  tensile  strength,  and  an  actual  breaking  down  of 
the  fibre  itself.  But  mercerized  cotton  shows  no  such  change;  on 
the  other  hand,  its  tensile  strength  is  considerably  increased,  and 
the  fibre-cell  shows  no  tendency  toward  physical  decomposition. 
3.  Changes  in  Cotton  Fibre  by  Mercerizing. — When  the 
cotton  fibre  is  immersed  in  a  concentrated  solution  of  caustic 
soda  it  undergoes  a  peculiar  physical  modification;  it  appears 
to  absorb  the  alkali,  swelling  to  a  cylindrical  form,  so  that  it 
presents  more  the  appearance  of  a  hair  than  a  flat  ribbon;  the 
fibre  also  untwists  itself  and  becomes  much  straighter,f  at 

*  There  is  considerable  difference  in  hydration  and  hydrolysis  in  the  case  of 
cellulose;  while  cotton  may  be  converted  apparently  into  a  hydrated  cellulose 
without  structural  disintegration,  where  it  is  converted  into  hydrocellulose  (by 
the  action  of  dilute  acids)  the  structure  and  consequently  the  strength  of  the 
fibre  is  destroyed.  Both  hydration  and  hydrolysis,  however,  under  certain 
conditions  may  occur  simultaneously.  The  hydrated  celluloses  (of  which  there 
may  be  many  varying  in  degree  of  hydration)  are  characterized  by  high  hygro1 
scopic  moisture,  whereas  the  hydrocelluloses  are  abnormally  low  in  this  respect. 
Hydrated  celluloses,  where  the  original  structure  of  the  fibre  is  retained  (mer- 
cerized cotton),  have  high  tensile  strength,  but  in  hydrated  celluloses  of  an 
amorphous  character  (the  artificial  silks)  the  tensile  strength  is  low.  All  hydrated 
celluloses  are  characterized  by  a  diminished  resistance  to  hydrolysis  by  acids 
to  an  extent  proportional  to  their  "degree  of  hydration." 

f  The  physical  changes  in  the  appearance  of  the  cdtton  fibre  when  mercerized  have 
been  studied  by  Hiibner  and  Pope  (Jour.  Soc.  Chem.  Ind.,  1904,  p.  404)  as  follows: 
Strength  of  Soda  Solution.  Effect. 

To  15°  Tw No  apparent  change 

16°  to  18° Slight  but  incomplete  twisting 

20° Initial  untwisting  followed  by  slow  uncoiling  of  the  twist 

26° Rapid  and  slow  uncoiling  become  one,  lasting  5  seconds 

40° Untwisting  and  uncoiling  take  place  together 

60°  to  8oc Swelling  precedes  untwisting 


MERCERIZED  COTTON  313 

the  same  time  shrinking  considerably  in  length.  The  internal 
portion  of  the  fibre  acquires  a  gelatinous  appearance,  becom- 
ing somewhat  translucent  to  light,  though  it  is  firm  in  structure ; 
the  surface  of  the  fibre  shows  a  wrinkled  appearance  transversely, 
due  to  a  somewhat  unequal  distension  of  the  inner  part.  There 
is  a  small  degree  of  lustre  on  portions  of  the  surface,  but,  due  to 
the  uneven  stretching  and  wrinkling  of  the  external  superficies, 
the  smooth  lustrous  portions  are  irregular  in  occurrence  and  not 
very  extensive  in  area.  The  fibre  also  shows  a  slight  increase 
in  weight.  These  changes  in  the  physical  appearance  of  the 
fibre  are  accompanied  by  a  remarkable  increase  in  the  tensile 
strength,  amounting  in  most  cases  to  as  much  as  from  30  to  50 
per  cent;  the  fibre  also  acquiring  a  greater  power  of  absorption 
toward  many  solutions,  most  notably  those  of  dyestuffs.  The 
increase  in  tensile  strength  is  probably  due  to  the  fact  that 
mercerizing  causes  the  inner  structure  of  the  fibre  to  become 
more  solidly  bound  together  by  a  filling  up  of  the  interstitial 
spaces  between  the  molecular  components  of  the  cell- wall. 
In  this  manner  the  fibre  as  a  whole  is  given  a  greater  degree  of 
solidity;  the  internal  strain  between  the  cell-elements  (which 
must  be  quite  considerable  after  the  drying  out  and  shrinking 
of  the  ripened  fibre)  is  lessened  no  doubt,  and  hence  adds  to 
the  unified  strength  of  the  fibre.  From  the  fact  that  the  fibre 
shrinks  in  length  in  mercerizing,  it  is  probable  that  the  cell- 
elements  have  contracted  transversely  on  the  collapse  of  the 
fibre  canal,  and,  on  being  distended  again  by  the  action  of  the 
caustic  alkali,  these  cell-elements  become  shortened  longitu- 
dinally and  •  are  more  tightly  packed  together.  The  increased 
affinity  for  dyestuffs  exhibited  by  mercerized  cotton  is  not  to 
be  considered  a  new  inherent  property  of  the  modified  cellulose 
induced  by  a  change  in  its  chemical  composition.  It  is  no 
doubt  a  result  of  the  modified  physical  structure  of  the  fibre 
itself;  that  is,  when  the  cell-elements  have  become  distended, 
like  a  sponge,  they  have  a  greater  power  of  absorption  and  reten- 
tion of  liquids  than  when  in  a  flattened  and  collapsed  condition. 
The  high  lustre  imparted  to  cotton  by  mercerizing  is  brought 
about  by  other  conditions  than  the  mere  action  of  the  caustic 


314  THE  TEXTILE  FIBRES 

alkali.*  In  the  swelling  of  the  cell-walls  and  consequent  con- 
traction of  the  fibre,  the  surface  remains  wrinkled  and  uneven, 
due  to  the  unequal  strain  of  expansion.  If,  however,  the  ends 
of  the  fibre  are  fixed,  and  thus  prevented  from  contracting  when 
subjected  to  the  chemical  action  of  the  alkali,  the  swelling  of 
the  cell-walls  will  cause  the  surface  to  become  smooth  and  even, 
and  similar  to  a  polished  surface  capable  of  reflecting  light  with 
but  little  scattering  of  the  rays.  Hiibner  and  Pope  f  have 


FIG.  70. — Mercerized  Cotton.     (X35o.)     (Micrograph  by  author.) 

observed  that  in  mercerizing  cotton  the  ribbon-like  fibre  becomes 
untwisted,  and  consider  that  this  change  of  twist  is  of  great 
importance  in  the  production  of  the  lustre.  They  further 
point  out  that  up  to  a  concentration  of  40°  Tw.  the  swelling 
action  of  the  caustic  lye  follows  the  untwisting;  while  at  con- 

*  It  has  been  claimed  that  the  mercerizing  effect  may  be  obtained  without 
tension  by  the  addition  of  glucose  to  the  alkaline  bath.  The  addition  of  other 
substances,  such  as  ether,  aluminium  chloride,  etc.,  have  been  claimed  to  pro- 
duce the  same  result.  But  it  is  to  be  doubted  whether  a  high  lustre  is  obtained 
by  any  of  these  methods. 

f  Jour.  Soc.  Chem.  Itid.,  1904,  p.  404. 


MERCERIZED  COTTON  315 

centrations  above  40°  Tw.  the  untwisting  follows  the  swelling. 
As  40°  Tw.  is  the  lowest  concentration  at  which  effective 
mercerization  is  brought  about,  it  is  considered  that  the  pro- 
duction of  a  lustre  on  cotton  is  necessarily  connected  with  that 
action  of  the  caustic  soda,  causing  an  untwisting  of  the  fibre 
to  take  place.  Another  condition  which  also  has  much  to  do 
with  the  production  of  the  lustrous  appearance  is  no  doubt  to 
be  found  in  the  physical  modification  of  the  cell  elements  them- 
selves. When  the  fibre  swells  up  under  the  action  of  the  caustic 
alkali,  its  substance  becomes  gelatinous  and  translucent,  and 
this  has  a  marked  effect  on  the  optical  properties  of  the  fibre 
and  enhances  the  lustre  considerably  by  lessening  the  propor- 
tion of  light  absorbed.* 

Considerable  difference  is  to  be  observed  in  the  strength 
and  elasticity  of  cotton  mercerized  without  tension  and  that 
mercerized  with  tension.  Buntrock,  in  a  research  on  this  sub- 
ject, found  that  cotton  yarn  mercerized  without  tension  showed 
an  increase  of  68  per  cent  in  its  tensile  strength,  f  whereas  the 

*  Dr.  Frankel  has  advanced  the  opinion  that  the  high  lustre  exhibited  by 
mercerized  cotton  is  mainly  due  to  the  fibre  having  lost  its  thin  cuticle  during 
the  process.  But  this  theory  is  overthrown  by  the  fact  that  if  mercerized  cotton 
is  again  subjected  to  the  action  of  cold  strong  caustic  soda,  it  contracts  nearly  as 
much  as  raw  cotton  would  do,  and  loses  its  silky  lustre  entirely.  According 
to  Minajeff  (Zeit.  Farben-Ind.,  1908,  pp.  i  and  17)  the  cuticle  is  still  present  in 
both  mercerized  and  bleached  cotton.  The  cuticle  contains  as  incrusting  bodies, 
fat,  wax,  coloring  matter,  and  a  substance  called  cutin,  which  is  insoluble  in 
sulphuric  acid.  Processes  in  which  alkaline  agents  are  used,  such  as  mercerizing, 
boiling-out,  and  bleaching,  will  remove  the  waxy  and  fatty  bodies,  but  not  the 
cuticle  itself.  In  some  cases  it  is  difficult  to  distinguish  the  cuticle  under  the 
microscope.  Minajeff  in  studying  the  action  of  some  reagents  on  the  cotton 
fibre  under  the  microscope  arrived  at  the  following  conclusions:  The  cuticle  of 
the  raw  cotton  fibre  resists  treatment  with  concentrated  cuprammonium  solu- 
tion, fairly  strong  sulphuric  acid  (but  not  the  concentrated  acid),  and  concen- 
trated alkaline  liquors  both  during  boiling  and  mercerization.  The  cuticle  of 
the  bleached  fibre  has  the  same  properties  as  those  of  the  unbleached,  though 
not  to  the  same  extent. 

t  Grosheintz  gives  the  following  results  of  some  experiments  on  the  effect  of 
mercerization  on  the  tensile  strength  of  cotton:  Unmercerized  yarn  broke  with  a 
load  of  356-360  grams;  same  yarn  mercerized  in  cold  aqueous  caustic  soda  (35°  Be.) 
broke  with  530-570  grams;  same  yarn  mercerized  with  cold  alcoholic  caustic 
soda  (10  per  cent)  broke  with  600-645  grams;  same  (except  that  hot  alcoholic 
caustic  soda  was  used)  broke  with  a  load  of  690-740  grams. 


316  THE   TEXTILE   FIBRES 

same  cotton  mercerized  under  tension  gave  an  increase  of  only 
35  per  cent.*  With  respect  to  the  elasticity  of  the  yarn,  the 
same  chemist  ascertained  that  the  untreated  cotton  employed 
in  his  experiments  stretched  n  per  cent  of  its  length  before 
breaking;  the  amount  for  cotton  mercerized  without  tension 
was  17  per  cent,  an  increase  of  54  per  cent;  cotton  mercerized 
under  tension  showed  no  increase  in  elasticity  at  all,  and  could 
only  be  stretched  the  original  u  per  cent  before  breaking. 
These  figures,  of  course,  are  not  absolute  for  all  varieties  of  cot- 
ton, but  will  vary  within  considerable  limits,  depending  upon 
the  character  of  the  raw  cotton  employed.  Attention  must 
also  be  drawn  to  the  fact  that  the  figures  for  the  tensile  strength 
and  elasticity  quoted  above  were  obtained  by  using  spun  yarn 
and  are  not  based  on  the  single  fibre.  Of  course  it  is  the  strength 
of  the  yarn  which  is  desired  in  practice,  but  the  figure  for  this 
is  not  necessarily  that  for  the  fibre  itself.  In  mercerizing  yarn 
or  cloth,  it  must  be  borne  in  mind  that  the  fibres  shrink  con- 
siderably, and  in  doing  so  become  more  closely  knit  together; 
therefore  the  increase  in  tensile  strength,  as  ascertained  by 
Buntrock,  represents  really  the  greater  coherence  of  the  fibres 
to  one  another  rather  than  an  increase  in  the  strength  of  the 
individual  fibre,  because  in  breaking  a  yarn  spun  from  a  large 
number  of  fibres  there  is  little  or  no  actual  breaking  of  the 
fibres  themselves,  but  only  a  pulling  apart  of  the  latter.  The 
same  criticism  also  applies  to  a  determination  of  the  elasticity. 
It  would,  perhaps,  be  more  scientific  to  determine  the  break- 
ing strain  and  elasticity  of  the  separate  fibres  rather  than  that 
of  the  yarn  or  cloth;  but  it  may  be  assumed,  with  considerable 
show  of  reason,  that  these  figures  of  Buntrock  will  represent 
a  fair  relation  between  the  strength  and  elasticity  of  the  individual 
fibres.  The  cause  of  the  lesser  increase  in  tensile  strength  of 
cotton  mercerized  under  tension  as  compared  with  that  of  the 
same  cotton  mercerized  without  tension  is  to  be  attributed  to 

*  According  to  Bowman  (Structure  of  Cotton  Fibre,  p.  227)  the  increase  in 
strength  of  single  cotton  yarns  (20/1  to  60/1)  by  mercerization  is  about  32  per 
cent  and  for  twofold  yarns  50  per  cent.  The  yarns  were  mercerized  without 
tension  in  cold  caustic  soda  solution  of  1.35  sp.gr.,  but  rinsed  under  tension. 


MERCERIZED  COTTON  317 

the  fact  that  when  the  shrinkage  of  the  fibre  is  prevented  by 
the  application  of  an  external  force  the  cell  tissues  cannot 
become  as  compact  as  otherwise,  and  there  is  also  an  internal 
strain  induced  which  lessens  the  ultimate  strength  of  the  fibre. 
This  latter  condition  also  accounts  for  the  lack  of  any  increase  in 
the  elasticity  of  the  mercerized  fibre;  the  fibre  when  mercerized 
under  tension  is  already  in  a  stretched  or  strained  condition, 
and  can  hardly  be  expected  to  give  the  same  degree  of  elasticity 
as  if  tension  had  not  been  applied,  as  a  certain  part  of  its  elas- 
ticity has  been  used  up  by  the  stretching. 

The  reaction  between  cotton  and  caustic  soda  in  the  mer- 
cerizing process  is  generally  considered  as  a  chemical  one. 
This  was  the  opinion  of  Mercer  himself,  and  was  supported  by 
Gladstone,  Cross  and  Bevan,  Beltzer  and  many  other  prominent 
chemists.  Recently,  however,  Ristenpart  has  advanced  the 
idea  that  the  process  of  mercerization  is  principally  an  osmotic 
action,  and  the  contraction  which  the  cotton  undergoes  when 
mercerization  is  unaccompanied  by  tension  is  due  to  purely 
physical  causes.*  The  cotton  fibre  is  surrounded  by  a  hardened 
cuticle,  and  this  acts  as  a  dialysing  membrane  to  induce 
osmotic  action,  when  the  fibre  is  steeped  in  a  strong  solution 
of  caustic  soda,  the  water  tends  to  diffuse  faster  from  the  fibre 
into  the  surrounding  liquid,  while  the  soda  tends  to  diffuse 
faster  into  the  fibre.  This  osmotic  condition  demands  an 
increased  pressure  within  the  fibre,  causing  it  to  swell.  In 

*  Miller  (Berichte,  1910,  p.  3430)  is  of  the  opinion  that  mercerized  cotton  does 
not  represent  a  cellulose  hydrate.  If  the  material  is  dried  at  95°  C.  before  and 
after  mercerization,  a  slight  loss  of  weight  is  recorded,  instead  of  a  gain,  as  a 
result  of  the  treatment.  The  hygroscopic  moisture  of  mercerized  cotton  is  the 
same  whether  the  sample  be  dried  at  95°  C.  in  an  oven  or  at  25°  C.  over  calcium 
chloride.  A  hydrate  stable  between  these  extremes  of  temperature  is  hardly 
conceivable.  When  dried  in  vacuo  over  sulphuric  acid,  mercerized  cotton 
has  the  same  percentage  composition  as  cotton  itself.  On  the  other  hand,  mer- 
cerized cotton  behaves  differently  from  ordinary  cotton  in  certain  chemical 
reactions;  it  also  shows  an  increased  adsorption  capacity  for  atmospheric  moisture, 
dyestuffs,  etc.  From  these  facts  Miller  contends  that  in  the  process  of  merceriza- 
tion the  sodium  hydroxide  enters  into  a  state  of  solid  solution  in  the  cellulose 
and  this  process  is  accompanied  by  a  partial  conversion  of  the  cellulose  into  an 
isomeride,  the  extent  of  this  conversion  depending  on  the  concentration  of  the 
alkali. 


318  THE   TEXTILE  FIBRES 

doing  this  it  will  naturally  assume  a  form  which  will  give  it 
the  greatest  internal  capacity  for  a  minimum  surface,  hence  the 
fibre  contracts  in  length  and  tends  to  assume  a  straight 
cylindrical  form. 

4.  Conditions  of  Mercerizing.  Chemicals  Employed. — The 
proper  conditions  for  carrying  into  practical  operation  the 
mercerizing  process  are  simple  and  easily  realized.  Caustic 
soda  is  the  most  suitable  and  convenient  reagent  *  for  bringing 
about  the  hydra tion  of  the  cellulose;  and  it  has  been  found  that 
a  solution  of  density  between  60°  and  70°  Tw.  gives  the  best 
results.!  Caustic  soda  solutions  of  less  density  than  15°  Tw. 
have  but  little  action  on  cotton;  the  maximum  effect  appears 
to  be  produced  by  a  concentration  of  about  60°  Tw.,  though  the 
difference  between  this  and  that  obtained  at  50°  Tw.  is  not 
very  marked,  and  even  at  40°  Tw.  the  mercerizing  action  of 
the  alkali  is  quite  strong.  Other  reagents  than  caustic  alkalies, 
however,  may  be  employed  for  the  hydrolysis  of  the  cottor. 
Concentrated  mineral  acids,  such,  for  instance,  as  sulphuric 
acid  at  a  density  of  100°  to  125°  Tw.,  will  bring  about  the 
mercerizing  effect  more  or  less  perfectly;{  the  same  is  also  true 

*  Solutions  of  caustic  potash  probably  give  a  somewhat  better  lustre,  and  the 
shrinkage  of  the  fibre  is  less  than  with  caustic  soda.  But  these  small  advantages 
are  not  sufficient  to  compensate  for  the  extra  expense  which  would  be  entailed  by 
the  use  of  caustic  potash. 

f  Vieweg  (Berichte,  1907,  p.  3876)  found  that  cotton  absorbed  caustic  soda 
from  a  1 6  per  cent  solution  to  form  a  compound  of  the  formula,  Ci2H2oOio-NaOH, 
while  from  solutions  containing  35  per  cent  of  caustic  soda  the  cellulose  com- 
pound corresponded  to  the  formula,  Ci2H2oOi<r  2NaOH.  Hiibner  and  Teltscher 
(Jour.  Soc.  Chem.  Ind.,  1909,  p.  643),  however,  find  that  the  maximum  absorp- 
tion of  caustic  soda  not  subsequently  removed  by  washing  with  absolute 
alcohol,  occurs  at  a  strength  of  40°  Tw.,  while  less  alkali  is  taken  up  from 
stronger  solutions;  and  contrary  to  the  opinion  of  Gladstone  and  Vieweg,  they 
find  no  evidence  inferring  the  existence  of  soda  celluloses  as  distinct  chemical 
compounds. 

|  Mercer  is  his  original  patent  describes  the  use  of  concentrated  sulphuric 
acid,  zinc  chloride,  and  phosphoric  acid  as  mercerizing  agents.  Htibner  and  Pope 
(Jour.  Soc.  Chem.  Ind.,  1904,  p.  409)  find  that  cotton  yarn  steeped  in  sulphuric 
acid  of  114°  Tw.  shows  a  contraction  of  9.5  per  cent.  When  immersed  in  the 
stretched  condition  a  perceptible  lustre  is  obtained.  A  50  per  cent  solution  of 
zinc  chloride  caused  a  contraction  of  2.3  per  cent,  and  where  acting  on  the 
stretched  yarn  gave  a  slight  lustre.  Nitric  acid  of  83°  Tw.  caused  a  contraction 


MERCERIZED  COTTON  319 

of  certain  metallic  salts,  most  notably  the  chlorides  of  zinc, 
calcium,  and  tin.*  Beyond  a  mere  theoretical  and  chemical 
interest,  however,  mercerizing  by  means  of  such  reagents  has  no 
practical  value,  f  The  addition  of  various  chemicals,  how- 
ever, has  been  made  to  the  caustic  alkali  solution  with  beneficial 
results.  It  has  been  observed,  for  instance,  that  the  addition 
of  zinc  oxide  has  a  very  marked  effect.  {  The  addition  of 

of  9.5  per  cent,  and  when  treated  under  tension  the  yarn  showed  some  lustre. 
Concentrated  hydrochloric  acid  caused  a  contraction  of  1.8  per  cent,  and  a  slight 
degree  of  lustre  was  developed  under  tension.  A  30  per  cent  solution  of  sodium 
sulphide  caused  a  contraction  of  1.3  per  cent  and  a  slight  degree  of  lustre  could 
be  developed  by  stretching.  In  none  of  these  cases,  however,  was  the  mercerizing 
effect  at  all  comparable  to  that  obtained  by  the  ordinary  process  with  caustic  soda. 

*  Hiibner  and  Pope  (Jour.  Soc.  Chem.  Ind.,  1904,  p.  404)  have  shown  that 
the  mercerizing  effect  may  be  produced  with  strong  solutions  of  potassium  iodide, 
the  fibre  retaining  15  per  cent  of  the  salt  and  showing  an  increased  affinity  for 
many  dyes. 

f  The  use  of  sulphide  of  sodium  or  potassium  instead  of  caustic  alkali  has 
been  proposed;  but  the  process  yields  very  poor  results.  It  is  claimed  that  by 
adding  ether  to  the  caustic  soda  solution  good  mercerization  can  be  obtained 
with  but  little  contraction  of  the  fibre,  but  as  this  process  requires  fifty  parts  of 
ether  to  twenty  parts  of  caustic  soda  solution,  the  expense  renders  it  ridiculously 
impracticable.  It  is  said  that  the  addition  of  carbon  bisulphide  to  the  bath  of 
caustic  soda  very  materially  increases  the  lustre;  this  causes  a  disintegration  of 
the  fibre,  however,  through  the  formation  of  viscose  (see  p.  298) ;  hence  the  treat- 
ment should  be  very  brief,  otherwise  the  cotton  will  be  seriously  tendered.  The 
mercerized  fibre  is  first  as  stiff  as  horse-hair,  but  this  effect  can  be  removed  by 
repeated  washing.  The  sulphur  can  be  removed  from  the  cotton  by  washing  in 
a  solution  of  sal-ammoniac,  and  this  should  be  done  before  the  material  is  treated 
with  an  acid  bath,  as  the  latter  would  cause  a  precipitation  of  sulphur  on  the 
fibre  and  so  spoil  the  lustre. 

t  A  solution  of  caustic  soda  of  13°  Be.  has  but  a  slight  mercerizing  effect, 
but  by  the  addition  of  i  part  of  zinc  hydrate  (Zn(OH)2)  to  4  parts  of  caustic  soda 
(NaOH),  the  mercerizing  effect  is  greatly  increased.  The  addition  of  ammo- 
niacal  hydrates  of  copper  and  nickel  also  have  the  same  effect. 

Vieweg  (Berichte,  1908,  p.  3269)  asserts  that  the  addition  of  sodium  chloride 
materially  increases  the  absorption  of  caustic  soda  by  cotton  in  mercerizing. 
Miller  (Jour.  Russ.  Chem.  Phys.  Gesell.,  1905,  p.  361),  however,  states  that  the 
absorption  of  caustic  soda  by  cellulose  is  not  influenced  by  the  presence  of  either 
sodium  chloride  or  sodium  carbonate.  Hiibner  (Jour.  Soc.  Chem.  Ind.,  1909, 
p.  228)  shows  that  the  presence  of  sodium  chloride  materially  reduces  the  mer- 
cerizing effect  (shrinkage  and  lustre)  of  caustic  soda  solutions.  When  examined 
under  the  microscope  the  untwisting  of  the  fibres  is  also  slower  and  less  complete. 
Knecht  (Jour.  Soc.  Chem.  Ind.,  1909,  p.  228)  has  also  carefully  tested  the  effect 
of  mercerizing  with  and  without  the  addition  of  salt,  and  his  results  show  that 


320 


THE  TEXTILE   FIBRES 


glycerol,  though  perhaps  of  some  benefit  in  assisting  in  the 
even  and  thorough  penetration  of  the  liquor  into  the  fibre, 
can  hardly  be  said  to  appreciably  modify  the  general  operation 
of  the  alkali.*  Previous  treatment  with  Turkey-red  oil  is  also 
of  benefit  for  the  same  reason;  this  is  also  true  of  such  sub- 
stances as  sodium  silicate. f  sodium  aluminate,  and  soap.J 

5.  Temperature  of  Mercerizing. — The  temperature  at  which 
the  reaction  is  carried  out  should  not  be  higher  than  the  usual 
atmospheric  degree;  in  fact,  it  has  been  recommended  to  lower 
the  temperature  of  the  caustic  soda  solution  by  the  addition 
of  ice,  but  this  procedure  does  not  appear  to  add  anything  of 


the  contraction  of  the  fibre  and  the  affinity  for  dyestuffs  is  lessened  by  the  addition 
of  salt.  He  gives  the  following  table  showing  the  quantitative  absorption  of 
several  dyestuffs: 


Dyestuff. 

Untreated  Cotton. 

Mercerized  with 
Caustic  Soda  Alone. 

Mercerized  with 
Caustic  Soda  and 
Salt. 

Per  Cent. 

Per  Cent. 

Per  Cent. 

Diamine  sky  blue  

1.  06 

1.6,6 

1-25 

Chrysophenine  

0.74 

1.17 

I  .Ol 

Benzopurpurin  46  

1  .02 

I.Q7 

1.67 

It  would  seem  therefore  that  Vieweg's  assertion  that  the  addition  of  sodium 
chloride  to  the  caustic  soda  solution  increased  the  mercerizing  effect  is  erroneous. 
It  has  further  been  demonstrated  that  the  addition  of  salt  to  the  caustic  lye  always 
decreases  the  lustre  of  the  mercerized  cotton. 

*  In  the  practical  manipulation  of  the  mercerizing  process  it  has  been  found 
that  the  impregnation  with  caustic  liquor  is  greatly  facilitated  by  the  addition  of 
5  per  cent  of  alcohol  on  the  weight  of  the  caustic  soda. 

f  The  addition  of  sodium  silicate  or  glycerin  to  the  mercerizing  lye  has  been 
found  to  retard  the  swelling  and  shrinkage  of  the  fibres,  and  therefore  the  lustre 
obtained  is  inferior.  (See  Hiibner  and  Pope,  Jour.  Soc.  Chem.  Ind.,  1904,  p.  409.) 

t  Fabrics  of  vegetable  fibres  (cotton  or  linen)  may  also  be  mercerized  in 
patterns  by  printing  on  certain  compounds  capable  of  resisting  the  action  of  the 
caustic  soda  in  the  subsequent  mercerizing  process.  Resists  suitable  for  this 
purpose  are,  in  the  first  place,  organic  compounds  which  readily  coagulate,  such 
as  albumin  and  casein;  and,  secondly,  such  salts,  acids,  or  oxides  which  may 
act  by  neutralizing  the  caustic  alkali,  or  from  which  a  hydrate  may  be  precipi- 
tated on  the  fabric  by  its  action.  Such  compounds,  for  instance,  as  the  salts  of 
aluminium  or  zinc,  organic  acids,  and  the  oxides  of  zinc,  aluminium,  or  chromium 
are  quite  suitable.  Very  beautiful  effects  are  said  to  be  obtainable  by  this 
process. 


MERCERIZED  COTTON  321 

material  advantage.*  At  elevated  temperatures  caustic  soda 
appears  to  exert  a  destructive  effect  on  cotton,  probably  due 
to  the  formation  of  oxycellulose  through  hydrolysis  and  subse- 
quent oxidation.  Beyond  a  certain  temperature  the  mercerizing 
effect  rapidly  diminishes,  and  at  the  boil  it  is  scarcely  appre- 
ciable, f  The  best  results  appear  to  be  obtained  when  the 
temperature  is  maintained  at  20°  C.  or  lower.  Above  this  point 
the  contraction  of  the  fibre  (which  may  be  taken  as  a  measure 
of  the  degree  of  mercerization)  grows  less  and  less  with  rise  of 
temperature. 

In  practice,  it  is  necessary  that  the  caustic  soda  solution 
should  be  maintained  at  a  uniform  density  and  temperature, 
otherwise  successive  lots  of  the  mercerized  material  will  differ 
in  their  degree  of  mercerization.  In  the  case  of  yarns,  this 
unevenness  may  not  be  apparent  until  the  material  is  dyed. 
To  bring  about  a  uniform  result  it  is  necessary  to  maintain  a 
constant  circulation  of  the  caustic  liquors  through  the  merceriz- 
ing machine  (whatever  mechanical  system  may  be  employed), 
adding  systematically  the  necessary  amount  of  strong  caustic 
at  a  constant  degree  of  density.  Practice  shows  that  a  pound  of 
cotton  yarn  requires  from  0.5  to  0.75  pound  of  solid  caustic  soda 
(98  per  cent  NaOH)  for  mercerization.  As  considerable  heat  is 
developed  in  the  mercerizing  process,  it  may  be  necessary  to 
employ  an  artificial  cooling  device  to  keep  the  temperature  of 
the  caustic  liquor  at  a  constant  point.  This  is  generally 
accomplished  by  passing  the  caustic  liquor  during  its  circulation 

*Lefevre  (Rev.  Gen.  Mat.  Col.,  1902,  p.  i)  states  that  a  solution  of  caustic 
soda  of  35°  Be.  at  a  low  temperature  gives  the  same  mercerizing  effect  as  a 
solution  of  50°  Be.  at  ordinary  temperatures.  Kurz  considers  that  with  raw 
cotton  it  is  advantageous  to  use  cooled  solutions  of  caustic  soda,  but  with  bleached 
cotton  it  is  not  necessary,  as  the  rise  in  temperature  of  mercerizing  the  latter 
is  small,  whereas  with  raw  cotton  a  rise  in  temperature  of  13°  to  21°  C.  is  to  be 
noticed. 

f  Beltzer,  however,  claims  that  caustic  soda  solutions  of  65°  Tw.  gave  the 
same  results  in  mercerizing  at  90°  C.  as  at  15°  C.,  but  the  cotton  mercerized  at 
the  higher  temperature  was  much  more  transparent  than  the  other.  The  lustre, 
however,  was  in  no  wise  inferior.  If  the  mercerization  be  conducted  at  90°  C., 
it  is  necessary  to  keep  the  cotton  entirely  immersed,  to  guard  it  from  contact  with 
the  air,  otherwise  it  will  become  seriously  weakened. 


322 


THE  TEXTILE   FIBRES 


through  a  tank  provided  with  a  coil  of  pipes  supplied  with 
cold  water.  It  is  only  necessary  to  keep  the  caustic  liquor  below 
a  temperature  of  75°  F.,  in  order  to  obtain  good  results. 


60  80 

Temperatures. 


120  °C 


FIG.  71. — Curves  showing  contraction  of  cotton  mercerized  at  different  temper- 
atures and  with  different  concentrations  of  alkali. 

It  has  been  found  that  the  degree  of  lustering  decreases 
very  materially  with  the  increase  of  temperature,*  as  is  shown 

*  Beltzer,  Rev.  Gen.  Mat.  Col.,  1902,  pp.  25  and  34. 


MERCERIZED  COTTON 


323 


graphically  in  the  preceding  curves  (Fig.  71).  On  examining 
these  curves  it  will  be  noted  that  a  characteristic  phenomenon 
takes  place  when  we  pass  from  caustic  soda  solutions  of.  15° 
Be.  to  those  of  25°  Be.  At  a  concentration  of  15°  Be.  the 
curve  representing  the  contraction  is  convex  toward  the  axes 
of  the  co-ordinates,  whereas  for  concentrations  over  15°  Be. 
the  curve  is  concave.  At  a  certain  mean  concentration  (20° 
Be.)  the  curve  should  become  a  straight  line.* 

The  following  tablet  shows  the  contraction  (degree  of 
mercerization)  of  cotton  yarns  obtained  with  different  concen- 
trations of  caustic  soda  and  at  different  temperatures  for  periods 
of  i,  10,  and  30  minutes.  The  contraction  is  expressed  in 
percentages- 


Density  of  Caustic  Soda  Solutions. 

5°B6. 

10°  B6. 

15°  Be. 

25  Be. 

30°  Be. 

35°  Be, 

Duration  of  Mercerizing  in  Minutes. 

i 

[0 

30 

i 

10 

30 

i 

10 

30 

i 

10 

30 

i 

IO 

30 

i 

10 

30 

0 

0 

0 

i 

I 

I 

12.2 

15.2 

16.8 

19.2 

20.  i 

21.  S 

22.7 

22.7 

22.7 

23-5 

23.0 

23.0 

0 

0 

0 

0 

0 

0 

8 

8.8 

II.  8 

19.2 

20.1 

21.  I 

22.5 

22.5 

22.5 

23-5 

23.0 

21.0 

0 

o 

0 

0 

o 

0 

4.6 

4.6 

6.0 

19.2 

20.3 

19.0 

19.8 

19.8 

19.8 

20.7 

20.5 

20.1 

0 

0 

o 

0 

o 

0 

3-5 

3-7 

3-8 

13-4 

13-7 

14.2 

.5.5 

15.5 

15-5 

15.5 

15.5 

15-4 

6.  Time  of  Mercerizing. — The  mercerizing  action  of  caustic 
soda  is  rather  a  rapid  one,  as  it  requires  only  a  few  minutes 
for  its  completion;  in  fact,  it  appears  to  take  place  simul- 
taneously with  the  impregnation  of  the  fibre  by  the  liquid. { 
In  ten  minutes  mercerization  is  practically  complete,  and  length- 
ening of  the  time  does  not  increase  the  mercerizing  effect  ;§ 

*  Beltzer,  VInd.  Text.,  1908,  p.  118. 

f  Gardner,  Die  Mercerisation  der  Baumwolle. 

J  For  small  periods  of  immersion  the  contraction  varies  in  proportion  to  the 
time  up  to  about  twenty  seconds;  the  lustre  reaches  its  maximum  in  about  this 
period  of  time.  (Beltzer,  Les  Matter -cs  Cellulosiques,  p.  65.) 

§  Miller  (Berkhte,  1007,  p.  7902)  has  established  the  fact  that  cotton  absorbs 
less  alkali  after  a  prolonged  immersion  than  with  a  shorter  immersion.  When 


324 


THE  TEXTILE  FIBRES 


in  fact,  too  long  a  contact  of  the  cotton  with  the  caustic  alkali 
is  to  be  avoided,  especially  if  the  impregnated  fibre  is  exposed 
to  the  air,  as  there  is  danger  of  a  breaking  down  of  the  cellular 
structure  and  a  consequent  deterioration  in  the  strength  of  the 
fibre.  The  time  of  immersion  also  appears  to  be  independent 
of  both  the  temperature  and  the  concentration  of  the  alkali.* 
7.  Tension  in  Mercerizing. — There  are  two  ways  in  which 
the  tension  may  be  applied  in  mercerizing:  (a)  The  material 
may  be  held  in  a  state  of  tension  during  the  time  of  its  treatment 
with  the  caustic  alkali,  and  until  the  alkali  has  been  washed 
out,  in  which  case  the  tension  should  be  so  maintained  that 
the  material  cannot  shrink ;  (b)  the  tension  may  be  applied  after 
the  material  has  been  treated  with  the  caustic  alkali,  but  before 
the  latter  is  washed  out,  in  which  case  sufficient  tension  should 
be  exerted  to  stretch  the  material  back  to  its  original  length. 
If  the  tension  is  not  applied  until  after  the  alkali  has  been  removed 
from  the  fibre,  no  lustring  effect  is  produced;  it  is  absolutely 
essential  that  the  stretching  should  take  place  while  the  fibre 
is  in  the  form  of  an  alkali-cellulose,  and  before  it  has  been  con- 
verted by  treatment  with  water  into  hydrated  cellulose. 

TOO  grams  of  cotton  were  steeped  in  caustic  soda  solution  of  28°  Be.  the  absorption 
of  alkali  was  as  follows: 

T^.  Alkali  Absorbed, 

Time*  Per  Cent. 

30  seconds 2 . 69 

i  hour 2 . 53 

24  hours 2 .  50 

*  The  following  table  shows  the  relations  existing  bretween  the  contraction 
of  the  yarn,  the  amount  of  benzopurpurin  fixed,  and  the  duration  of  mercerizing. 
The  mercerizing  was  done  with  caustic  soda  solution  of  29°  B6. 


Time  of  Merceriza- 
tion.    Seconds. 

Contraction. 
Per  Cent. 

Dyestuff  Fixed. 
Per  Cent. 

I 

15-7 

3-24 

IO 

17-4 

3-62 

20 

25.0 

3-80 

40 

25.0 

3.89 

60 

25.0 

3  Qi 

120 

27.0 

4.10 

MERCERIZED   COTTON  325 

According  to  the  experiments  of  Herbig,  the  stretching  force 
necessary  to  keep  the  cotton  in  its  original  length  during  mercer- 
ization  is  only  from  a  quarter  to  a  Jthird  of  that  necessary  to 
do  the  stretching  after  mercerization ;  but  there  appears  to  be 
no  appreciable  difference  in  the  lustre  obtained.  It  would 
appear,  however,  that  stretching  beyond  a  certain  point  ceases 
to  increase  the  lustre,  and  to  obtain  the  maximum  lustering 
effect  it  is  not  necessary  to  stretch  the  cotton  back  to  its  original 
length.  Herbig  concluded  that  stretching  during  merceriza- 
tion is  disadvantageous,  and  it  is  best  to  mercerize  the  yarn 
loose,  wring  it,  and  only  stretch  while  rinsing,  as  the  required 
stretching  force  is  then  quite  small.  The  best  time  for  stretch- 
ing, then, 'is  during  the  conversion  of  the  soda-cellulose  into 
the  hydrocellulose.  If  the  stretching  does  not  take  place  until 
after  rinsing,  almost  twice  the  force  is  necessary  to  restore  the 
yarn  to  its  original  length,  as  when  in  contact  with  the  lye, 
and  the  lustre  is  decidedly  inferior.  The  stretching  force  also 
appears  to  depend  on  the  twist,  being  greater  in  proportion  as 
the  twist  is  harder. 

Herbig  gives  a  summary  of  his  experimental  results  as 
follows : 

1.  Loose  yarn  mercerized  without  any  stretching,  whether 
long-  or  short-stapled,  and  whether  with  or  without  a  hard 
twist,  has  less  lustre  than  unmercerized  yarn.     But  even  with 
a  very  slight  tension  the  lustre  is  greater. 

2.  Both  with  long-  and  short-stapled  cotton  the  lustre  only 
becomes  marked  when  the  stretching  force  is  sufficient  to  bring 
the  yarn  back  to  its  original  length. 

3.  Stretching  beyond  the  original  length  does  not  give  any 
increase  in  lustre. 

4.  Considerable  difference  is  observable  in  the    stretching 
force  needed  between  loose  mercerization  followed  by  stretching 
in  the  lye,  and  keeping  the  cotton  at  its  original  length  during 
mercerization,   as  in   the   latter   case   only  one-third   to   one- 
quarter  of  the  force  is  necessary  to  produce  the  silky  lustre. 

5.  The  stretching  of  the  yarn  requires  only  a  small  force 
when  mercerized  loose  and  if  applied  when  rinsing  is  actually 


326  THE  TEXTILE  FIBRES 

in  progress;   for  the  best  time  for  stretching  is  during  the  con- 
version of  the  soda-cellulose  into  hydrocellulose. 

6.  When  rinsing  is  over,  twice  as  much  force  is  needed  to 
restore  the  original  length  as  is  required  for  yarn  still  in  contact 
with  the  lye;   and  yarns  so  treated  contract  somewhat  on  dry- 
ing, and  exhibit  an  inferior  lustre. 

7.  The  stretching  force  necessary  in  mercerizing  yarn  varies 
with  the  twist,  and  in  general  is  greater  in  proportion  as  the 
twist  is  harder. 

8.  The  production  of    the   silky   lustre   does  not  depend 
primarily  on  the  amount  of  force  employed  in  stretching,  as 
soft  yarn  with  only  a  small  amount  of  twist  can  be  lustred. 

9.  The  production  of  the  silky  lustre  is  independent  of  the 
cotton  being  long-  or  short-stapled,  as  short-stapled  American 
cotton  with  even  a  loose  twist  can  be  given  a  silky  lustre. 

10.  The  production  of  a  high  degree  of  lustre  depends  to  a 
considerable  extent  on  the  fineness  of  the  fibre  and  its  natural 
lustre.     This  is  apparent  in  mercerizing  sea-island  and  Egyptian 
cotton. 

8.  Washing  as  a  Process  in  Mercerizing. — By  the  washing 
of  the  material  after  steeping  in  caustic  alkali,  a  twofold  object 
is  gained.  In  the  first  place,  the  action  of  the  water  on  the  alkali- 
cellulose  is  to  effect  a  chemical  transformation  into  cellulose 
hydrate,  and  this  action  is  as  really  essential  to  mercerizing  as  the 
action  of  the  caustic  soda  itself.  In  the  second  place,  the  wash- 
ing is  conducted  for  the  purpose  of  removing  all  excess  of  caustic 
alkali  from  the  material.*  Caustic  soda  is  held  quite  tenaciously 
by  cotton,  and  it  requires  a  very  thorough  and  long-continued 
washing  to  remove  the  last  traces  of  this  compound.  In  order 
to  shorten  the  period  required  for  washing,  it  is  customary  to  give 
the  cotton  first  a  rinsing  in  warm  water,  after  which  the  tension 
may  be  relieved,  and  then  to  wash  with  cold  water  and  then  with 

*  When  mercerized  cotton  is  rinsed  with  ammonia  instead  of  water  it  retains 

.its  gelatinous,  parchment-like  consistency  throughout  the  rinsing,  and  can  be 

stretched  to  its  original  length  without  breaking.     If  the  cotton  is  then  rinsed  with 

water  while  still  stretched,  the  fibre  regains  its  original  appearance  and  acquires 

.  a  lustre  as  good  as  that  obtained  in  the  usual  way. 


MERCERIZED  COTTON  327 

acidulated  water,  using  either  sulphuric  or  hydrochloric  acid  for 
this  purpose.  The  use  of  acetic  and  formic  acids  have  also  been 
tried,  but  their  expense  is  higher  than  sulphuric  acid.  The  strength 
of  the  acid  bath  should  be  so  adjusted  that  the  caustic  alkali 
is  completely  neutralized  without  unnecessarily  acidulating  the 
cotton.  To  remove  the  excess  of  acid,  however,  and  prevent 
subsequent  tendering  of  the  fibre,  the  cotton  should  be  thor- 
oughly washed  after  treatment  with  the  acid  and  finished  by 
soaping  or  oiling.  If  the  cotton  is  treated  with  a  soap  solution 
and  then  with  dilute  acetic  or  formic  acid  and  dried  without 
washing  out  the  excess  of  acid,*  the  fibre  will  be  found  to  have 
acquired  a  silk-like  "  scroop. "f  If  other  acids,  and  especially 
mineral  acids,  are  employed  for  washing,  a  subsequent  rinsing 
with  fresh  water  and  soaping  is  necessary  for  the  purpose  of 
neutralizing  all  of  the  acid,  which  would  otherwise  seriously 
tender  the  goods  on  drying,  unless  the  amount  of  acid  employed 
is  so  accurately  adjusted  as  not  to  leave  any  free  acid  in  the  fibre. 
9.  Quality  of  Fibre  for  Mercerizing. — The  character  of  the 
fibre  employed  has  a  considerable  influence  on  the  success  of  the 
mercerizing  process.  From  the  very  nature  of  the  fact  that  a 
considerable  degree  of  tension  must  be  applied  to  the  fibre 
during  the  process  in  order  to  obtain  the  desired  lustre,  it  would 
be  natural  to  expect  that  the  longer  the  staple  of  the  fibre  the 
more  readily  would  it  lend  itself  to  the  requirements  of  the 
operation.  And  such,  indeed,  is  found  to  be  the  case;  the  long- 
stapled  sea-island  and  Egyptian  varieties  of  cotton  are  those 

*  Mercerized  cotton  goods  that  have  been  dyed  with  sulphur  colors  and  then 
treated  with  soap  and  acid  baths  in  order  to  impart  scroop,  are  liable  to  be 
tendered  on  long  storing.  To  avoid  this  the  addition  of  sodium  acetate  (5  to 
10  grams  per  litre)  to  the  acid  bath  (10  grams  of  acetic  acid  per  litre)  has  been 
suggested.  According  to  an  English  patent  No.  11,729  of  1909,  a  better  method 
is  to  work  the  dyed  cotton  in  a  soap  bath,  hydro-extract,  and  without  washing, 
treat  in  a  bath  containing  17  grams  of  lactic  acid  and  7  grams  of  soda  ash  per 
litre  for  twenty  minutes,  hydro-extract,  and  dry  without  washing. 

t  A  "scroop"  may  also  be  imparted  to  mercerized  yarn  as  follows:  The  yarn  is 
soaped  in  a  lukewarm  (120°  F.)  bath  containing  8  per  cent  of  olive  oil  soap  and 
i  per  cent  of  starch  (on  the  weight  of  the  yarn);  then  hydro-extracted  and  treated' 
for  ten  minutes  in  a  bath  containing  TOO  gallons  water,  3  pounds  tartaric  acid, 
and  10  pounds  sodium  acetate.     Hydro-extract  and  dry  without  rinsing. 


328  THE  TEXTILE  FIBRES 

especially  adapted  for  use  in  the  preparation  of  mercerized 
cotton,  while  the  shorter-stapled  varieties  are  but  little  employed 
for  this  purpose,  as  the  lustre  obtained  with  them  is  by  no  means 
as  pronounced. 

Besides  sea-island  and  Egyptian  cottons,  however,  there 
are  large  quantities  of  the  long-stapled  American  peeler  cottons 
employed  for  mercerizing  in  the  United  States.  Certain  varieties, 
such  as  the  Allen-seed  cotton  of  Mississippi,  are  especially 
adapted  to  purposes  of  mercerizing,  and  if  proper  care  be  taken 
in  the  preparation  of  the  yarn,  very  good  effects  may  be  obtained. 
Boucart  *  gives  the  following  reasons  why  only  long-stapled 
cotton,  and  that  only  in  particular  counts,  gives  good  results 
on  mercerization.  A  simple  thread  consists  of  a  sort  of  twisted 
wick  composed  of  nearly  parallel  fibres.  The  twist  depends, 
as  regards  the  angles  it  makes  with  the  length  of  the  thread, 
both  upon  the  kind  of  cotton  and  upon  the  count  of  the  yarn. 
Of  the  two  sorts  of  simple  yarns,  warp-yarns  have  more  cohesion 
among  their  elements  than  tensile  strength,  while  the  reverse 
is  the  case  with  weft-yarns.  The  result  is  that  under  gradually 
increasing  tension  weft-fibres  slide  past  one  another  without 
breaking,  but  warp-fibres  break  before  any  such  occurrence 
takes  place.  The  degree  of  twist  also  depends  on  the  mean 
staple,  and  the  angle  between  the  thread  and  the  axis  at  any 
point  is  proportional  to  the  length  of  the  thread.  The  degree 
of  twist  which  is  required  to  make  the  cohesion  exceed  the  ten- 
sile strength  depends  naturally  on  the  strength  of  the  fibre. 
The  mercerizing  process  tends  to  shorten  each  individual 
fibre,  and  this  shortening  is  resisted  by  tension  in  the  direction 
parallel  to  the  axis  of  the  thread.  Hence  the  greater  the  angle 
the  thread  makes  with  that  axis  the  less  is  the  effect  of  the  ten- 
sion, and  if  any  portion  of  the  fibre  is  at  right  angles  to  the 
axis  it  is  not  affected  by  the  tension  at  all.  Hence  a  simple 
warp-thread  can  only  receive  a  medium  amount  of  gloss  from 
mercerization,  this  is  less  as  the  twist  is  greater.  Slightly 
twisted  threads  should  give  the  best  lustre,  but  if  the  cohesion 

*  Rev.  Gen.  Mat.  Col.,  1902,  p.  34. 


MERCERIZED  COTTON  329 

of  the  fibres  is  less  than  the  contractile  force  exerted  by  the  mer- 
cerizing, the  fibres  slip  past  each  other  and  no  lustre  is  produced. 
But  if  the  weft-threads  are  fixed,  as  in  piece  goods,  they  take 
a  better  lustre  than  the  warp,  although  the  latter  is  usually 
made  of  better  cotton.  Short-stapled  cotton  acquires  a  less 
degree  of  lustre  because  it  must  be  more  tightly  twisted.  The 
best  lustre  of  all  is  obtained  with  twofold  twist,  in  which  the 
outer  fibres  lie  parallel  to  the  axis,  and  the  yarn  should  be  well 
singed  to  remove  projecting  fibres. 

The  quality  of  being  mercerized,  is  not  an  inherent  property 
of  any  special  variety  of  cotton,  as  was  formerly  supposed  to  be 
the  case;  any  variety  of  cotton  is  capable  of  mercerization, 
the  essential  being  that  the  fibre  shall  be  maintained  in  a 
state  of  tension.  In  order  that  this  condition  be  realized  with 
short-stapled  fibres,  the  yarn  operated  upon  must  be  tightly 
twisted  in  order  to  present  sufficient  cohesion  among  the 
individual  fibres  to  allow  of  the  high  tension  required;  this, 
on  the  other  hand,  prevents  an  even  and  thorough  penetration 
of  the  caustic  alkali  into  the  substance  of  the  fibre,  so  that, 
on  the  whole,  the  results  obtained  with  short-stapled  fibres  are 
not  at  all  comparable  with  those  of  the  long-stapled  varieties. 

The  preparation  by  combing  of  cotton  for  mercerization 
has  a  considerable  influence  on  the  subsequent  lustre  of  the  yarn. 
Sea-island  cotton  possesses  a  rather  silky  fibre  to  begin  with, 
and  this  is  made  more  adaptable  to  the  production  of  a  high 
lustre  by  combing,  in  which  operation  the  fibres  are  arranged 
parallel,  and  still  further  by  gassing,  which  burns  off  the  minute 
outer  hairs.  Yarns  possessing  considerable  lustre  were  made 
in  this  manner  with  fine  counts  of  sea-island  cotton  long  before 
the  discovery  of  lustring  by  mercerization,  and  it  was  always 
recognized  that  the  parallelism  of  the  fibres  so  obtained  by 
combing  (and  sometimes  a  second  combing)  was  a  great  factor 
in  the  production  of  a  silky  and  lustrous  yarn.  By  later 
improvements  in  the  manner  of  applying  the  tension,  however, 
it  would  seem  that,  by  realizing  the  proper  mechanical  con- 
ditions, even  cotton  of  comparatively  short  staple  will  be  capable 
of  being  mercerized  in  a  more  successful  manner  than  heretofore. 


330  THE  TEXTILE  FIBRES 

10.  Methods  of  Mercerizing. — Cotton  is  largely  mercerized 
both  in  the  form  of  yarn  and  the  woven  fabric.  Yarn  mer- 
cerizing may  be  carried  out  in  the  skein  or  in  the  warp;  the 
latter  being  the  favorite  process  in  use  in  America,  while  in 
Europe  nearly  all  yarn  mercerizing  is  done  in  the  skein.  Machines 
for  skein  mercerizing  are  so  arranged  that  the  hanks  of  yarn  are 
stretched  between  revolving  rollers  and  successively  subjected 
to  the  action  of  caustic  soda,  a  washing  with  warm  water,  and 
finally  a  washing  with  cold  water.  The  operation  of  most  forms 
of  machines  is  entirely  automatic.  In  another  form  of  apparatus 
the  hanks  are  placed  over  a  perforated  horizontal  drum;  the 
latter  is  then  revolved  at  a  high  rate  of  speed  while  the  solution 
of  caustic  soda  is  applied  from  the  inside  and  the  washing  with 
water  is  done  in  the  same  manner.  The  tension  in  this  machine 
is  produced  by  the  centrifugal  force  arising  from  the  high  speed 
of  rotation.*  When  mercerized  in  the  form  of  warps  the  yarn 
is  passed  continuously  through  a  series  of  vats  in  which  it  is 
boiled-out,  treated  with  caustic  soda,  washed,  treated  with  dilute 
acid,  and  finally  finished  with  soap.  The  tension  is  obtained 
by  a  series  of  squeeze-rolls.  Warp  mercerizing  is  much  cheaper 
than  skein  mercerizing,  and  uniform  results  are  more  easily 
obtained.  Cloth  mercerizing  is  carried  out  on  an  apparatus 
resembling  a  long  tenter  frame  so  that  the  cloth  is  kept  in  ten- 
sion by  a  continuous  series  of  side  clamps.  As  the  cloth  moves 
along  this  frame  it  is  subjected  to  the  various  treatments  of 
caustic  soda,  washing  with  water,  and  neutralizing  with  dilute 
acid.  In  any  form  of  mercerizing  the  tension  may  be  released 
as  soon  as  the  strong  caustic  soda  is  removed  from  the  cotton 
by  washing;  it  is  not  necessary  that  all  of  the  caustic  soda  should 
be  removed  before  the  tension  is  slackened. 

Attempts  have  also  been  made  to  mercerize  cotton  in  the 
loose  state,  as  in  the  form  of  combed  sliver.  Ingenious  devices 
have  been  contrived  to  prevent  the  fibres  from  shrinking  during 
the  process.  In  one  form  of  apparatus  the  sliver  is  packed 

*  This  centrifugal  mercerizing  machine  was  devised  by  Kleinewefer,  and  was 
once  extensively  used.  We  understand,  however,  that  this  form  of  apparatus 
has  now  been  practically  abandoned  for  the  roller  type  of  machine. 


MERCERIZED  COTTON  331 

into  a  compact  mass,  and  the  mercerizing  solutions  are  forced 
through  it  by  means  of  a  vacuum  or  a  pump.  In  another 
machine  the  sliver  is  placed  between  two  perforated  sheets  of 
metal  pressed  tightly  together,  and  then  exposed  to  the  suc- 
cessive action  of  caustic  soda  and  water.  A  centrifugal  per- 
forated drum  rotating  at  a  high  speed  has  also  been  used  for 
mercerizing  cotton  sliver. 

Cotton  cloth  is  principally  mercerized  in  the  unbleached 
condition.  There  has  been  some  dispute  as  to  which  is  best: 
to  mercerize  first  and  bleach,  or  to  bleach  first  and  then  mercerize; 
experience,  however,  appears  to  favor  the  first  method.  In 
the  bleaching  operations,  which  usually  involve  a  rather  severe 
treatment  of  the  cotton  first  with  moderately  strong  alkalies, 
and  subsequently  with  solutions  of  bleaching  powder,  the 
fibre  suffers  more  or  less  chemical  alteration,  so  that  in  the 
mercerizing  process  it  can  no  longer  enter  into  proper  chemical 
union  with  the  caustic  soda  employed;  and  hence  complete 
true  mercerization  is  not  effected.  Although  cotton  should  be 
thoroughly  scoured  ("  boiled  out  ")  before  being  mercerized, 
it  is  best  not  to  use  alkalies  for  the  purpose,  but  to  employ 
Turkey-red  oil  (or  other  suitable  sulphated  oil)  or  soap.*  If 
bleaching  is  carefully  conducted  after  mercerizing,  the  injury 
to  the  lustre  of  the  fibre  is  very  slight.  Mercerized  cotton 
does  not  require  a  prolonged  boiling  in  alkalies  previous  to  the 
operation  of  bleaching  as  with  ordinary  cotton.  To  obtain 
the  best  conditions  for  high  lustre,  yarn  should  be  well  "  gassed  " 
(singed)  before  mercerizing,  as  otherwise  the  external,  hairy 
fibres  remain  loose  and  cannot  be  subjected  to  tension.  As 

*  Another  method  of  preparing  or  boiling-out  cotton  yarn  or  cloth  for  mer- 
cerizing is  to  steep  in  a  warm  liquor  containing  a  malt  preparation,  squeeze  out, 
and  allow  to  lay  overnight.  The  malt  preparation  causes  a  slight  fermentation 
in  the  pectin  substances  of  the  fibre  which  changes  them  to  soluble  compounds 
and  thus  permits  of  their  easy  removal.  It  also  tends  to  soften  the  fibre  so  it 
is  more  easily  penetrated  by  the  caustic  soda  solution  in  its  subsequent  treatment. 
Some  mercerizers  also  adopt  the  method  of  passing  the  yarn  through  a  boiling 
dilute  solution  of  soda  ash,  squeezing  out  excess  of  liquor,  and  then  allowing  to 
stand  overnight  piled  up  in  the  wet  state.  This  condition  also  induces  a  fermen- 
tation of  the  pectin  matters,  and  is  said  to  yield  a  somewhat  softer  yarn  after 
mercerizing. 


332  THE  TEXTILE  FIBRES 

a  result,  these  fibres  shrink,  and,  remaining  without  lustre  them- 
selves, hide  to  a  certain  extent  the  lustred  surface  of  the  yarn. 
Moreover,  caustic  soda  has  a  felting  action  on  these  free  fila- 
ments, and  felting  is  especially  detrimental  to  lustre. 

In  mercerizing  cloth  the  action  taking  place  between  the 
sizing  materials  (always  present  to  a  greater  or  lesser  degree  in 
cotton  cloth)  and  the  caustic  alkali  is  sufficient  at  times  to 
raise  the  temperature  considerably,  which  may  result  in  a 
deficient  lustre.  In  such  cases  recourse  must  be  had  to  artificial 
cooling  by  addition  of  ice  or  a  current  of  cold  water  in  order  to 
prevent  an  undue  rise  in  temperature. 

When  mercerized  cotton  is  to  be  bleached,  it  is  best,  after 
the  first  rinsing,  to  remove  the  major  portion  of  the  caustic  soda 
and  arrest  the  mercerization,  but  not  to  rinse  again  in  acidulated 
water,  as  would  ordinarily  be  done  if  the  material  were  not  to 
be  immediately  bleached.  The  small  amount  of  caustic  soda 
which  still  remains  in  the  cotton  acts  in  a  beneficial  manner 
in  bleaching. 

ii.  Recovery  of  Caustic  Soda  from  Mercerizing  Liquors. — 
As  the  caustic  soda  taken  up  by  the  cotton  in  its  mer- 
cerization has  to  be  all  removed  again  from  the  material 
before  the  process  is  completed,  it  may  readily  be  under- 
stood that  a  large  proportion  of  the  caustic  soda  must  be 
wasted  in  the  wash  waters  unless  proper  means  be  adopted  for 
its  recovery  and  purification.  In  the  economical  operation 
of  the  mercerizing  process  it  becomes  necessary  to  recover 
efficiently  the  caustic  soda  from  the  waste  wash  waters.  This 
requires  a  concentration  of  these  wash  waters,  and  a  purifica- 
tion of  the  lye  so  that  it  may  be  suitable  to  use  over  again. 

When  arrangement  is  made  for  the  recovery  of  the  caustic 
soda  it  is  best  to  use  the  wash  waters  in  such  a  manner  that 
when  the  material  first  emerges  from  the  mercerizing  liquor, 
and  is  consequently  heavily  saturated  with  caustic  soda,  it  is 
washed  by  water  already  containing  some  caustic  soda  derived 
from  previous  washing.  That  is  to  say,  the  mercerized  goods 
are  run  in  the  opposite  direction  to  the  flow  of  the  wash  water 
through  a  series  of  tanks,  so  that  the  final  washing  is  with 


MERCERIZED  COTTON  333 

fresh  water.*  This  allows  of  the  wash  water  in  its  final  use  to 
be  rather  well  concentrated,  and  consequently  it  can  be  more 
economically  evaporated.f 

The  wash  waters  become  contaminated  of  course  with  more 
or  less  foreign  matter  and  color  and  size  from  the  goods,  and 
there  is  also  formed  a  good  proportion  of  sodium  carbonate 
by  reason  of  the  exposure  of  the  caustic  soda  solution  to  the  air. 
The  purification  and  recaustification  of  these  liquors  are  carried 
out  by  mixing  in  a  tank  with  a  suitable  proportion  of  slaked 
lime  and  allowing  the  sludge  to  settle.  The  clear  purified 
liquor  is  drawn  off  and  evaporated  in  suitable  vacuum  evapora- 
tors until  concentrated  to  the  proper  degree  for  being  again 
available  for  use  (about  50°  Tw.). 

Recently  it  has  been  found  that  in  the  mercerizing  of  piece 
goods  a  very  economical  and  effective  method  of  washing  is 
by  the  use  of  steam  instead  of  water.  J  This  removes  the  caustic 
soda  from  the  cloth  much  quicker  and  gives  a  wash  water  of  a 
comparatively  high  concentration  (i4°-i6°Tw.),  so  that  the  cost 
of  subsequent  evaporation  is  low.  By  this  method  of  recovery 
from  96-98  per  cent  of  the  caustic  soda  may  be  regained. 

12.  Properties  of  Mercerized  Cotton. — Apart  from  its  high 
lustre  and  somewhat  increased  tensile  strength,  mercerized 
cotton  exhibits  but  few  apparent  differences  from  the  ordinary 
fibre.  Toward  dyestuffs  and  mordants  §  it  is  rather  more 
reactive,  1 1  and  consequently  will  dye  deeper  shades  with  the  same 

*  In  order  to  recover  economically  the  waste  casutic  soda  from  the  mercerized 
goods  it  is  necessary  to  obtain  the  waste  liquor  at  as  high  a  degree  of  concentration 
as  possible.  In  the  usual  washing  operation  as  generally  employed  after  mer- 
cerizing, the  waste  liquors  are  so  dilute  that  is  it  a  question  as  to  whether  it 
would  pay  to  purify  and  evaporate  them. 

t  See  Scott  &  Co.,  Eng.  Pat.,  19,734  of  1002. 

t  See  Matter,  Ger.  Pat.  215,045  of  1908;  also  Petzold,  Eng.  Pat.  20,656  of  1911. 

§  Wichellaus  and  Vieweg  have  studied  the  action  between  mercerized  cotton 
and  certain  metallic  oxides,  and  found  it  to  absorb  3.82  per  cent  of  barium 
hydrate  from  a  £  normal  solution,  and  2.18  per  cent  of  strontium  hydrate  from  a 
TV  normal  solution. 

||  Mercerized  cotton  exhibits  greater  chemical  activity  than  ordinary 
cotton.  In  preparing  artificial  silk  and  other  plastic  cellulose  materials  using 
viscose,  cuprammonium  cellulose,  or  cellulose  acetate  solutions,  it  is  nearly  always 
the  practice. to  start  with  mercerized  cellulose,  as  this  dissolves  much  better  in 
the  required  reagents  than  ordinary  cellulose. 


334 


THE  TEXTILE  FIBRES 


amount  of  dyestuff  than  ordinary  cotton;*  this  property  is  rather 

*  The  increased  affinity  of  mercerized  cotton  for  substantive  dyes  is  a  very 
characteristic  property.  Mercerized  cotton  requires  from  20  to  50  per  cent  less 
coloring  matter  than  ordinary  cotton  for  the  production  of  the  same  intensity 
of  color.  Knecht  (Jour.  Soc.  Dyers1  &  CoL,  1908,  p.  68)  has  made  comparative 
tests  with  various  mercerized  and  unmercerized  samples  of  cotton  in  order  to 
determine  the  quantity  of  coloring  matter  fixed  in  each  case.  The  dyestuff 
employed  was  benzopurpurin  4  B,  and  the  amount  of  dyestuff  fixed  was  deter- 
mined by  the  titanous  chloride  method,  A  summary  of  his  results  are  given 
in  the  following  table: 


Dyestuff  Fixed 

by  100  gms. 

of  Cotton. 


Nature  of  Cotton  Dyed. 


0.69 
2.78 
5-23 
i-55 
2.90 

3-39 


2.86 
3-54 


Ordinary  cotton  not  boiled  out. 
Cotton  mercerized  with  NaOH,  33°  Be". 
"       treated  with  HNO3  of  43°  Be. 
' '       boiled  out,  not  mercerized. 

mercerized  with  tension  with  NaOH  of  29°  Be. 
mercerized    without    tension    with    NaOH    at 

29°  Be. 
"       bleached,  not  mercerized. 

mercerized  with  tension  at  29°  Be". 
"  "  "          without  tension  at  20°  Be. 


The  next  table  gives  the  results  using  Egyptian  cotton  under  varying  con- 
ditions of  mercerizing: 


Dyestuff  Fixed 
by  100  gms. 
of  Cotton. 

Concentration  of  Caustic  Soda  Solution. 

1.77 

Unmercerized  cotton. 

1.88 

Mercerized  at  10°  Be. 

2-39 

14°  Be. 

2-57 

16°  Be. 

2.05 

19°  Be. 

3.02 

21.  5°  Be. 

3*-  15 

24°  Be. 

3-27 

26.  5°  Be. 

3.38 

29°  Be. 

3-50 

31°  B.? 

3.56 

33°  Be. 

3.60 

35-  5°  Be. 

3.66 

37-  5°  Be. 

The  last  table  shows  that  the  affinity  of  cotton  for  direct  dyestuffs  increases 


MERCERIZED  COTTON  335 

to  be  ascribed  to  the  increased  absorptivity  of  the  fibre  than 
as  the  result  of  any  chemical  modification  of  the  cellulose  com- 
posing it;  it  is  also  independent  of  the  method  of  mercerizing, 
that  is,  whether  accompanied  by  tension  or  not. 

Hiibner  and  Pope  *  have  studied  the  dyeing  properties  of 
mercerized  cotton  as  compared  with  ordinary  cotton  and  have 
shown  that  the  increase  in  the  absorption  of  dyestuff  is  dependent 
on  the  degree  of  mercerization.  Their  results  are  stated  as 
follows : 

(1)  Cold  caustic  soda  solution  of  i°  Tw.  has  a  considerable 
effect  in  increasing  the  affinity  of  cotton  f  for  substantive  dyes, 
and  from  o°  to  18°  Tw.  the  increase  in  affinity  for  the  dyestuff 
is   roughly  proportional   to   the   concentration   of   the   caustic 
soda. 

(2)  Between  18°  and  22°  Tw.  the  increase  in  the  concentra- 
tion of  the  soda  has  a  greater  effect  in  increasing  the  affinity 
of  the  cotton  for  the  color  than  corresponding  increases  of 
lower  concentrations.     With  soda  of  22°  to  26°  Tw.  the  effect 
becomes   still  greater,  and  from  26°  to  30°  Tw.  the  increased 
affinity  is  still  much  greater. 

(3)  Above  30°  Tw.,  however,  an  increase  in  the  strength 
of  the  caustic  soda  solution  has  less  effect  in  increasing  the 
affinity  for  dyes.     Between  55°  and  70°  Tw.  the  increase  in 
affinity  is  very  slight. 

(4)  When  mercerized   with   caustic   soda    solutions    above 
70°  Tw.  there  is  a  decrease  in  the  affinity,  so  that  cotton  mer- 
cerized with  caustic  soda  of  80°  Tw.  shows   the   same  dyeing 
power  as  that  mercerized  at  35°  Tw. 

Hiibner  and  Pope  have  also  studied  the  degree  of  contraction 
in  cotton  yarn  caused  by  treatment  with  caustic  soda  solutions 

in  proportion  to  the  degree  of  mercerization;  consequently,  the  degree  of  mer- 
cerization may  be  ascertained  by  the  quantity  of  benzopurpurin  fixed  by  100 
grams  of  cotton. 

*  Jour.  Soc.  Cheni.  Ind.,  1909,  p.  404. 

t  Though  dilute  solutions  of  caustic  soda  in  the  cold  have  the  effect  of  increas- 
ing the  dyeing  power  of  cotton,  such  solutions  used  hot  have  no  such  effect.  Cotton 
yarn  boiled  with  caustic  soda  solution  of  2°  Tw.  has  the  same  affinity  for  dyestuff s 
as  untreated  cotton.  • 


336 


THE  TEXTILE  FIBRES 


of  different  strengths.     The  following  table  shows  the  results 
of  their  tests: 


Strength  of 
NaOH, 
0  Tw. 

Length  of 
Hank, 
Yards. 

Contraction, 
"  Per  Cent. 

Strength  of 
NaOH, 
0  Tw. 

Length  of 
Hank, 
Yards. 

Contraction, 
Per  Cent. 



200 



2O 

186.8 

6.6 

o  (water) 

198 

1  .0 

22 

I7I-3 

14-3 

i 

196.4 

i-7 

24 

163.1 

18.4 

2 

105-7 

2.  I 

26 

160.3 

19.8 

3 

195.6 

2.2 

28 

160.0 

20.0 

4 

IQ5-5 

2.  2 

30 

158.2 

2O.9 

5 

J95.2 

2.4 

35 

150.2 

-4.9 

6 

194.2 

2-9 

40 

143-7 

28.1 

7 

193  7 

3-i 

45 

141.0 

29-5 

8 

194.2 

2.9  . 

50                   142.2 

28.9 

9 

194.0 

3-o 

55 

142.7 

28.6 

10 

194.2 

2.9 

60 

145-3 

27-3 

12 

194.5 

2-7         . 

65 

149.2 

25.4 

U 

192.7 

3-6 

70 

I50-3 

24.8 

16 

190.4 

4-8 

75 

152.8 

23.6 

18 

188.7 

5-6 

80 

154-2 

22.9 

It  will  be  noticed  that  at  about  20°  Tw.  there  is  a  sudden 
increase  in  the  amount  of  contraction,  and  that  a  maximum 
is  reached  at  about  45°  Tw. 

With  a  solution  of  iodin  in  potassium  iodide  mercerized 
cotton  exhibits  a  reaction  which  serves  to  distinguish  it  from 
ordinary  cotton.  By  immersing  samples  of  ordinary  and  mer- 
cerized cotton  for  a  few  seconds  in  a  solution  of  20  grams  of 
iodin  in  100  cc.  of  a  saturated  solution  of  potassium  iodide, 
then  washing  with  water,  the  ordinary  cotton  becomes  pale 
brown  while  the  mercerized  cotton  remains  black.  On  con- 
tinuing the  washing  the  ordinary  cotton  finally  becomes  colorless, 
while  the  mercerized  sample  remains  a  bluish  black,  which  fades 
only  very  slowly. 

On  treatment  of  cotton  with  a  i/ioo  normal  solution  of 
iodin,  and  exposing  the  sample  to  the  air,  ordinary  cotton 
becomes  nearly  decolorized  in  a  very  short  time,  while  mer- 
cerized cotton  will  exhibit  a  gradation  of  color  corresponding 
to  the  strength  of  caustic  soda  used  in  mercerizing.  It  also 


MERCERIZED  COTTON 


337 


appears  that  cotton  mercerized  without  tension  has  a  greater 
absorptive  power  for  iodin  than  cotton  stretched  during  the 
mercerization. 

Another  reagent  for  mercerized  cotton  is  a  solution  of  46 
grams  of  aluminium  chloride  in  100  cc.  of  water  to  which  is 
added  15  to  20  drops  of  iodin  solution.  On  steeping  mer- 
cerized cotton  in  this  solution  for  one  hour  it  gives  a  dark 
chocolate-brown  color,  while  ordinary  cotton  remains  colorless.* 

By  using  a  solution  containing  280  grams  of  zinc  chloride 
in  300  c.c.  of  water,  to  100  c.c.  of  which  are  added  20  drops  of 
a  solution  of  i  gram  of  iodin  and  20  grams  of  potassium  iodide 
in  100  c.c.  of  water,  more  distinctive  colorations  between 
ordinary  and  mercerized  cotton  can  be  obtained  than  is  the  case 
even  with  the  above  described  solution  of  iodin.  The  color 
given  by  this  reagent  on  ordinary  cotton  is  more  readily  removed, 
while  the  color  left  on  the  mercerized  cotton  is  more  persistent. 
By  use  of  this  solution  the  strength  of  caustic  soda  solution 
employed  in  the  mercerization  of  a  sample  may  be  determined,  f 

*  See  Hiibner,  Jour.  Soc.  Chem.  Ind.,  1908,  p.  no. 

t  Hiibner  (ibid,  1908,  p.  105)  gives  a  table  of  tests  showing  the  reaction 
of  this  reagent  on  cotton  samples  mercerized  with  different  strengths  of  caustic 
soda: 


Strength  of 
Caustic  Soda, 
0  Tw. 

I. 
20  Drops  of  Iodin 
Solution. 

II. 
10  Drops  of  Iodin 
Solution. 

III. 
5  Drops  of  Iodin 
Solution. 

0 

Slight  red  tint 

Remains  white 

Colorless 

IO 

Faint  red 

Very  faint  brown 

1  1 

2O 

Dark  chocolate 

Darker  brown 

(  t 

23 

Darker,  bluer 

Darker,  bluer 

t  « 

26 

Much  darker  and  bluer 

Much  darker  and  bluer 

<  < 

30 

Very  dark  navy  blue 

Darker,  reddish  blue 

Faint  blue 

40 

Black 

Much  darker 

Bluer 

50 

Black 

Darker  than  40 

Darker  blue 

60 

Black 

Darker  than  40 

Slightly  lighter 

70 

Black 

Darker  than  40 

Lighter 

The  different  proportions  of  the  iodin  solution  were  added  to  100  c.c.  of  the 
zinc  chloride  solution.  When  woven  fabrics  are  examined,  the  sample  should  be 
first  dipped  in  water  and  pressed  between  filter  paper  before  applying  the  reagent. 
Preliminary  removal  of  dyes  tuffs  does  not  interfere  with  the  test. 


338  THE  TEXTILE   FIBRES 

Another  characteristic  test  for  mercerized  cotton  is  its 
behavior  with  benzopurpurin.*  If  ordinary  cotton  and  mer- 
cerized cotton  be  dyed  with  benzopurpurin  in  a  dilute  dye- 
bath,  then  hydrochloric  acid  added  drop  by  drop  until  the 
ordinary  cotton  is  just  changed  to  a  blue  color,  the  mercerized 
cotton  will  still  remain  a  bright  red.f  This  test  was  first  pro- 
posed by  Knecht,  who  conducted  it  so  that  sufficient  hydro- 
chloric acid  was  added  to  change  both  samples  to  a  blue  color. 
Then  a  solution  of  titanous  chloride  was  added  cautiously  to 
the  liquid  until  just  before  decolorization  when  the  sample  of 
ordinary  cotton  remained  blue  while  that  of  the  mercerized 
cotton  became  red.f 

Higgins  §  has  shown  that  mercerized  cotton  is  more  hygro- 
scopic than  ordinary  cotton,  and  furthermore,  the  propor- 
tion of  moisture  absorbed  increases  with  the  "  degree  of  mer- 
cerization,"  as  shown  by  the  following  table:  1 1 


Degree  of  Mercerization. 

Moisture. 
Per  Cent. 

Ordinary  cotton 

6  20 

JVtercerized  with 

caustic  soda  10°  Tw 

6    37 

20°  Tw  

6  68 

« 

"                10°  Tw 

8    AO 

« 

O  rr\ 

40    1  w  >  

941 

(( 

"                50°  Tw    

94.3 

1  1 

"                60°  Tw 

9^7 

tt 

70°  Tw  

960 

*  In  carrying  out  this  test  care  must  be  had  to  use  only  pure  benzopurpurin, 
as  the  presence  of  safranin  or  other  compounds  usually  present  in  commercial 
samples  of  benzopurpurin  may  vitiate  the  delicacy  of  the  test. 

f  Knaggs,  Jour.  Soc.  Dyers'  6°  Col.,  1908,  p.  112.  The  fact  that  the  mercerized 
cotton  remains  red  is  evidently  not  due  to  any  residual  alkali  in  the  fibre,  for  if 
sufficient  acid  is  added  to  turn  the  color  of  the  mercerized  sample  to  a  blue,  and 
this  sample  is  immersed  again  in  the  dye  solution,  the  red  color  reappears. 

J  See  Jour.  Soc.  Dyers'  &*  Co/.,  1908,  p.  67. 

§  See  Jour.  Soc.  Chem.  Ind.,  1909,  p.  188. 

||  In  these  tests  cotton  yarn  was  well  boiled  out  and  mercerized  without  tension 
with  caustic  soda  solutions  of  different  strengths.  The  samples  were  then 
washed,  soured,  washed,  dried  at  60°  C.,  and  then  exposed  to  the  air  for  some 
time.  The  moisture  was  determined  by  weighing  before  and  after  drying  for 
eight  hours  at  100°  C. 


MERCERIZED  COTTON  339 

If  these  results  are  compared  it  will  be  noticed  that  a  sharp 
increase  is  evident  between  cotton  mercerized  at  20°  Tw.  and 
30°  Tw.,  while  beyond  40°  Tw.  the  moisture  becomes  practically 
constant.* 

13.  Cellulose  Hydrate.  Hydracellulose.—  As  previously  men- 
tioned mercerized  cotton  is  considered  to  be  an  alteration  prod- 
uct of  cellulose  known  as  cellullose  hydrate  or  hydracelluose. 
The  cellulose  is  supposed  to  have  united  with  a  molecule  of 
water  giving  CeHioOo-H^O.t  Hydracellulose  is  not  to  be 
confused  with  hydrocellulose  (see  p.  288),  as  in  the  latter  a 
distinct  rearrangement  in  the  molecule  takes  place,  the  cellu- 
lose being  hydrolyzed.  The  form  of  combination  of  the  water 
in  the  case  of  hydracellulose,  on  the  other  hand,  is  probably 
similar  to  that  in  various  crystalline  salts,  containing  water 
of  hydration  (or  crystallization). 

Hydracellulose  has  the  property  of  absorbing  a  greater 
proportion  of  alkali  from  dilute  caustic  soda  solutions  than 
non-hydrated  cotton,  as  shown  by  the  following  table,  using 
a  2  per  cent  solution  of  caustic  soda:t 


Character  of  Cotton.  Na°,H 

Ordinary  purified  cotton  ..........................   i 

Cotton  mercerized  in    8  per  cent  NaOH  .............   1.4 

"  16  per  cent  NaOH  .............   2.8 

Hydracellulose  of  viscose  silk§  .....................  4.5 

'  '  cuprate  silk  .......................  4.0 

*  Oxley  (Jour.  Soc.  Dyers'  &  Col..  1906)  states  that  mercerized  cotton  does 
not  dye  to  as  full  a  shade  after  drying  as  when  dyed  after  mercerizing  but 
before  drying.  It  has  also  been  found  that  ordinary  cotton  behaves  in  the  same 
manner.  It  is  also  known  that  cotton  cloth  which  has  been  thoroughly  dried, 
even  after  a  long  exposure  to  the  atmosphere,  will  not  absorb  the  amount  of 
moisture  it  originally  contained  in  the  air-dry  state.  (See  Higgins,  Jour.  Soc. 
Chem.  Ind.,  1909,  p.  188.) 

t  The  researches  of  Ost  and  Westhoff  (Chem.  Zeit.,  1909,  p.  197)  on  "cellulose 
hydrates"  (including  mercerized  cotton)  indicate  that  when  these  substances 
are  freed  from  all  traces  of  hygroscopic  moisture  they  have  the  same  composition 
as  ordinary  cellulose,  i.e.,  C6Hi0O5.  Hydrocelluloses,  on  the  other  hand,  appear 
to  contain  chemically  combined  water. 

J  The  amount  of  alkali  absorbed  by  hydracellulose  does  not  increase  beyond 
2.8  per  cent  even  if  the  concentration  of  the  mercerizing  bath  is  above  16  per 
cent  NaOH.  It  also  seems  to  be  independent  of  the  temperature  of  the  solution. 

§  Attention  may  also  be  called  to  the  manner  in  which  different  hydracelluloses 


340 


THE  TEXTILE  FIBRES 


It  may,  therefore,  be  concluded  that  there  exist  various 
degrees  of  hydration  of  cotton,  and  these  may  be  determined  by 
the  proportion  of  caustic  soda  absorbed.  That  is  to  say,  the 
degree  of  hydration  may  be  measured  by  the  quantity  of  alkali 
(NaOH)  absorbed  by  100  grams  of  cotton  when  treated  with 
a  2  per  cent  solution  of  caustic  soda.  The  following  table 
shows  this  degree  of  hydration:* 


Concentration  of 
Mercerizing  Liquor, 
Per  Cent  NaOH. 

NaOH  Absorbed  per 
100  Grams  of  Cotton. 

Unmercerized 

I 

4 

I 

8 

1-4 

12 

1.8 

16 

2.8 

20 

2.8 

24 

2.8 

Hydracellulose  may  also  be  formed  by  the  action  of  concen- 
trated acids  under  proper  conditions,  f  This  accounts  for 

behave  with  caustic  soda  solutions  of  high  concentration.  It  is  known  that  the. 
viscose  and  cuprate  artificial  silks  belong  to  the  same  general  class  of  hydra- 
celluloses  as  mercerized  cotton.  In  fact,  they  are  scarcely  to  be  distinguished 
in  their  reducing  properties.  Between  these  artificial  silks,  however,  and  mer- 
cerized cotton,  there  apparently  exists  a  marked  contrast  as  to  the  degree  of 
hydration.  The  former  when  treated  with  strong  caustic  soda  solutions  and  washed 
with  water,  become  gelatinous  and  almost  completely  dissolve.  Mercerized 
cotton,  on  the  other  hand,  remains  insoluble.  The  artificial  silks  consist  of  cellulose 
regenerated  from  solutions,  and  perhaps  consist  of  cellulose  molecules  which  have 
not  suffered  much  condensation,  whereas  mercerized  cotton  may  consist  of  highly 
condensed  polymers  of  the  simple  cellulose  molecule,  hence  its  dissociation  is 
much  more  difficult.  (See  Cross  and  Schwalbe,  Berichte,  1911.  p.  151.) 

*  The  practical  determination  of  the  degree  of  hydration  of  mercerized  cotton 
may  be  made  according  to  the  following  method:  There  is  placed  in  a  flask  200  c.c 
of  a  2  per  cent  solution  of  caustic  soda;  50  c.c.  of  this  solution  is  titrated  with 
N/2  sulphuric  acid.  In  the  remaining  solution  there  is  placed  3  grams  of  air- 
dried  cotton.  After  agitating  for  thirty  minutes,  50  c.c.  of  the  solution  is  again 
titrated  with  N/2  sulphuric  acid.  The  difference  in  the  titrations  will  indicate 
the  amount  of  alkali  absorbed  by  the  cotton.  (Vieweg,  Berichte,  1908,  p.  3269.) 

f  When  cotton  is  treated  with  a  solution  of  sulphuric  acid  of  51°  Be.,  washed, 
and  dried,  the  product  may  be  dissolved  in  a  moderately  concentrated  solution 
of  caustic  soda  (like  viscose  or  cuprate  silks).  When  hydrated  cotton  is  triturated 


MERCERIZED  COTTON  341 

the  mercerizing  effect  of  such  acids.  The  same  is  also  true  of 
the  action  of  the  double  iodide  of  barium  and  mercury  and  of 
solutions  of  zinc  chloride  on  cotton;  hydracellulose  is  produced 
in  each  case,  and  a  mercerizing  effect  is  obtained. 

14.  Microscopy  of  Mercerized  Cotton. — Microscopically  the 
mercerized  cotton  fibre  exhibits  a  considerable  difference  from 
that  of  ordinary  cotton.  Whereas  the  latter,  when  viewed 
under  the  microscope,  appears  as  a  twisted  flat  band  with 
thickened  edges,  and  in  cross-section  like  a  collapsed  tube, 
mercerized  cotton  appears  as  a  rather  smooth  cylindrical  fibre, 
the  cross-section  of  which  is  more  or  less  circular.  It  rarely 
happens  that  a  fibre  absolutely  loses  all  of  its  twist,  though  the 
degree  of  mercerization  may  be  measured  by  the  freedom  of 
the  fibre  from  irregularities  and  twists.  Under  ordinary  con- 
ditions when  the  cotton  is  mercerized  in  a  state  of  tension,  it 
will  also  be  found  that  many  fibres  will  remain  in  their  original 
form,  or  unmercerized,  whereas  others  will  be  mercerized  only 
in  portions  of  their  length.  The  microscopical  examination 
of  mercerized  cotton  is  important  in  determining  just  how 
per  ectly  the  process  has  been  carried  out,  which  may  be  judged 
by  the  relative  number  of  unmercerized  or  partially  mercerized 
fibres  which  may  be  present.* 


with  a  solution  of  caustic  soda  sufficiently  concentrated  to  produce  mercerization, 
there  is  obtained  a  viscous  liquid  which  may  be  likened  to  a  colloidal  solution. 
This  solution  may  be  passed  through  a  filter-press,  and  in  this  manner  there  is 
finally  obtained  a  homogeneous  viscous  liquid  that  can  be  flocculated  by  the  addi- 
tion of  an  acid.  The  precipitate  of  regenerated  cellulose  may  be  separated  by 
ordinary  filtration.  (See  L 'Industrie  Textile,  1911,  p.  74.) 

*  Hanausek  (Microscopy  of  Technical  Products,  p.  66)  gives  the  following 
description  of  the  microscopy  of  mercerized  cotton:  The  fibres  are  broad,  straight, 
round,  and  smooth,  with  a  lumen  which  is  either  visible  the  entire  length,  although 
narrow  and  varying  in  breadth,  or  only  occasionally  visible  so  that  the  fibre 
shows  a  row  of  streaks,  or  it  may  be  quite  invisible.  Humps  and  depressions, 
corresponding  to  folds  and  twists  of  the  original  fibre,  are  frequently  present. 
The  fibres  without  evident  lumen,  closely  resemble  silk  fibres,  but  treatment 
with  cuprammonia  brings  out  the  lumen,  and  at  the  same  time,  certain  marked 
differences  between  untreated  and  mercerized  fibres.  The  latter  swell  uniformly 
in  the  reagent,  without  marked  constrictions  and  the  lumen  does  not  become 
folded  or  coiled,  since  the  fibre  does  not  contract  in  length.  The  uniform  swelling 
is  explained  by  the  absence  of  the  cuticle;  only  in  rare  cases,  where  the  fibre  has 


342  THE  TEXTILE  FIBRES 

15.  Schreiner  Finish. — A  silky  lustre  resembling  that  pro- 
duced by  mercerization  can  be  given  to  cotton  cloth  by  means 
of  what  is  known  as  a  calender  finish.  This  is  accomplished 
by  passing  the  cloth  between  rollers  under  heavy  pressure, 
one  of  the  rollers  being  engraved  with  obliquely  set  lines  ruled 
from  125  to  600  to  the  inch.  The  effect  is  to  produce  a  great 
number  of  parallel,  flat  surfaces  on  the  cloth,  which  causes  it 
to  acquire  a  high  lustre.  By  conducting  the  operation  with 
hot  rollers  quite  a  permanent  finish  can  be  produced  which 
closely  approximates  mercerized  cotton.  Cloth  so  finished, 
however,  loses  its  lustre  in  a  large  degree  on  washing.  The 
method  is  chiefly  known  as  the  "  Schreiner  process." 

obviously  escaped  the  action  of  the  mercerizing  liquid,  is  the  cuticle  present. 
Sometimes  the  inner  tube  is  alternately  enlarged  and  contracted,  presenting  in 
surface  view  the  appearance  of  a  series  of  rhomboids.  In  cross-section  the  fibres 
are  nearly  circular,  with  groups  of  minute  granules  as  contents. 


CHAPTER  XIV 
THE  MINOR  SEED  HAIRS 

i.  Bombax  Cotton. — Besides  the  cotton  derived  from  the 
ordinary  species  of  the  cotton  plant  (Gassy pium  family),  there 
is  a  very  similar  seed-hair  fibre  obtained  from  a  plant  known  as 
the  cotton-tree  and  belonging  to  the  Bombacece  family.  The 
fibre  is  known  in  trade  as  vegetable  down  or  bombax  cotton.  It 
grows  almost  exclusively  in  tropical  countries.  The  fibre  is 
soft,  but  rather  weak  as  compared  with  ordinary  cotton;  in 
color  it  varies  from  white  to  a  yellowish  brown,  and  it  is  quite 
lustrous.  The  fibres  have  a  length  of  from  10  to  30  mm.,  and 
a  diameter  of  from  0.020  to  0.045  mm-  Owing  to  its  weakness 
and  lack  of  elasticity,  bombax  cotton  is  not  used  by  itself  as  a 
textile  fibre;  it  is  sometimes  mixed  with  ordinary  cotton  and 
spun  into  yarn,  but  it  is  principally  used  as  a  wadding  and 
upholstery  material. 

In  its  physical  appearance,  bombax  cotton  differs  from  true 
cotton  in  not  possessing  any  spiral  twist  and  showing  irregular 
thickenings  of  the  cell-wall;  the  fibre  usually  consists  of  one 
cell,  though  occasionally  it  may  have  two.  Unlike  true  cotton, 
the  fibre  does  not  grow  directly  from  the  seed,  but  originates 
at  the  inner  side  of  the  seed-capsule. 

There  are  several  varieties  of  plants  from  which  vegetable 
down  may  be  obtained.*  In  Brazil  it  is  obtained  from  the 
Bombax  heptaphyllum  and  B.  ceiba,  and  the  product  is  known 
as  Paina  limpa  or  ceiba  cotton.  This  is  also  produced  in  the 
West  Indies  and  other  parts  of  tropical  America.  In  Bombax 

*  All  the  varieties  of  Bombax  cotton  are  very  similar  in  appearance  and  prop- 
erties, and  it  is  practically  impossible  to  discriminate  between  them  with  any 
degree  of  certainty. 

343 


344 


THE  TEXTILE   FIBRES 


ceiba  the  fibre  has  a  length  of  from  i  to  1.5  cm.,  while  in  B. 
heptaphyllum  the  fibre  length  is  from  2  to  3  cm.,  being  by  far 
the  longest  and  strongest  variety  of  bombax  cotton.  B. 
malabaricum,  of  South  Asia  and  Africa,  has  fibres  from  i  to  2 
cm.  in  length;  this  latter  is  known  in  India  as  Simal  cotton  or 
red  silk-cotton.  Other  varieties  of  Bombax  plants  are  B. 
cumanense  of  Venezuela,  giving  a  product  known  as  "  lana 


FIG.  72. — Vegetable  Down.     (Ochroma  Lagopus.)     (X35o.) 

E,  lace-like  structure  at  base;    F,  fibre  folded  on  itself;    P,  point  of  fibre;  C,  thin 
cell-wall.     (Micrograph  by  author.) 

del  tambor  "  or  "  land  vegetale;"  B.  pubescens  and  B.  mllosum 
from  Brazil;  B.  carolinum  from  South  America;  B.  rhodogna- 
phalon  of  West  Africa,  the  fibre  of  which  is  known  as  wild 
kapok  and  is  used  largely  for  the  stuffing  of  pillows  and 
mattresses. 

The  microscopical  characteristics  of  vegetable  down  are  as 
follows:  The  fibre  consists  of  a  single  cell,  possessing  a  cylindrical 


THE  MINOR   SEED  HAIRS  345 

shape,  being  rather  thick  at  the  base  and  tapering  gradually 
to  the  point.  The  base  of  the  fibre  is  frequently  swollen  and 
exhibits  a  lace-like  structure  (see  Fig.  72).  The  cell- wall  is 
usually  very  thin,  occupying  not  more  than  one- tenth  the  width 
of  the  fibre,  while  the  cuticle  is  well  developed.  The  cross- 
section  is  circular  and  not  flat,  as  in  the  case  of  cotton,  and  is 
from  20-40  [L  broad.  The  inner  canal  is  partly  filled  with  a 
dried-up  protoplasmic  membrane. 

In  its  chemical  constitution  vegetable  down  differs  from 
ordinary  cotton  in  containing  a  certain  amount  of  lignified 
tissue;  consequently  it  furnishes  a  yellow  coloration  when 
treated  with  anilin  sulphate  or  with  iodin  and  sulphuric  acid, 
and  by  these  tests  it  may  readily  be  distinguished  from  true 
cotton.  Owing  to  its  lignified  nature  the  fibres  also  swell 
but  slightly  when  treated  with  Schweitzer's  reagent.  The 
fibre  from  the  Bombax  ceiba  is  distinguished  by  its  decidedly 
yellowish  color.* 

2.  Kapok. — The  seed-hairs  of  the  Eriodendron  anfractuosum 
(or  Bombax  pentandrum)  are  very  similar  to  the  preceding 
varieties  of  vegetable  down.  It  gives  the  product  known  in 
Holland  as  kapok.  In  both  their  physical  appearance  and  chem- 
ical properties  it  is  almost  impossible  to  distinguish  between 
kapok  and  ceiba.  cotton.  Kapok  is  obtained  from  South  Asia 
and  the  East  Indies,  and  is  very  extensively  used  as  upholstery 
material,  and  also  for  the  stuffing  of  life-saving  belts  on  account 
of  its  low  specific  gravity.f 

When  examined  microscopically  kapok  is  seen  to  have  a 
tapering  cylindrical  form,  the  fibre  consisting  of  a  single  cell 
with  a  bulbous  base.  It  is  soft  and  lustrous  but  deficient  in 
elasticity,  hence  is  too  brittle  for  purposes  of  spinning.  The 
fibre  resembles  a  smooth  transparent  structureless  rod,  fre- 
quently doubled  over  on  itself.  Like  the  bombax  cottons, 

*  None  of  the  varieties  of  the  bombax  cottons  is  a  pure  white,  but  vary 
in  color  from  pale  yellow  to  brown.  The  paina  llmpa  is  the  lightest  in  color. 

t  It  is  stated  that  in  the  compressed  condition  kapok  can  support  about 
thirty-six  times  its  weight  in  water,  and  it  has  the  advantage  over  cork  of  drying 
quickly.  Kapok  has  also  been  used  in  surgery  as  a  substitute  for  absorbent 
cotton. 


346 


THE  TEXTILE  FIBRES 


kapok  contains  lignocellulose,  hence  gives  the  yellowish  brown 
coloration  with  iodin  and  sulphuric  acid.  The  following  are 
analyses  of  kapok  from  different  sources : 


Lagos  Kapok. 
Per  Cent. 

Java  Kapok. 
Per  Cent. 

Seychelleo   Kapok. 
Per  Cent. 

IMoisture 

9n 

IO   0 

IO    OO 

Ash      .    .  .           

2.8 

I  .3 

2.08 

Cellulose 

">o  3 

63  6 

6  1   30 

The  hair-fibres  of  the  Ochroma  lagopus  (from  the  West 
Indies)  have  a  length  of  from  0.5  to  1.5  cm.,  and  are  thicker 
(6-7  a)  in  the  middle  than  at  the  ends.  The  cell-wall  is  much 
thicker  than  with  bombax  cotton,  and  the  fibres  are  also  more 
lignified  than  those  of  the  latter.  The  walls  are  especially 
thick  at  the  base  and  apex  and  here  show  the  presence  of  granular 
matter.  Vegetable  down  occurs  in  trade  as  edredon  vegetate 
or  pattes  de  lievre,  and  the  product  comes  mostly  from  Guade- 
loupe and  Martinique.  The  typical  fibres  show  a  deep  yellow 
color  under  the  miscroscope;  others  are  nearly  colorless,  flat- 
tened, often  much  folded,  with  indistinct  outline  and  finely 
striated  surface.  The  typical  fibres  have  a  breadth  of  25-50  UL. 
The  Ouate  vegetale  of  the  French  trade  is  a  mixture  of  fibres 
from  Bombax,  Ochroma,  and  Chorisia  varieties.  It  is  chiefly 
used  for  the  stuffing  of  mattresses,  cushions,  etc. 

The  Cochlospermum  gossypium  of  India  and  the  Chorisia 
speciosa  and  C.  insignis  of  South  America  also  furnish  fair 
qualities  of  vegetable  down.  They  are  known  as  Kumbi  or 
Galgal,  and  are  used  for  stuffing  cushions.  The  fibres  of  C. 
insignis  swell  up  when  placed  in  water. 

}  Pulu  fibre  can  also  be  classed  under  the  general  name  of 
vegetable  down.  It  is  the  hair  obtained  from  the  stems  of  fern- 
trees,  more  especially  the  Cibotium  glaucum  of  the  Hawaiian 
Islands.  The  fibres  are  lustrous,  of  a  golden-brown  color,  very 
soft,  and  not  especially  strong.  They  have  a  length  of  about 
5  cms.,  and  are  composed  of  a  series  of  very  flat  cells,  pressed 
together  in  a  ribbon-like  form.  The  fibre  is  only  employed  as 


THE   MINOR  SEED-HAIRS  347 

an  upholstery  material  and  is  never  spun.  Similar  fibres  are 
also  obtained  from  Cibotium  barometz,  C.  menziesii,  and  C. 
chamissoi;  the  second  one  produces  the  best  fibre. 

3.  Vegetable  Silk. — Another  seed-hair  which  is  utilized 
to  some  extent  as  a  fibre  is  the  so-called  vegetable  silk  or  Asclepias 
cotton.  Though  the  fibre  presents  a  beautiful  silky  appearance 
it  is  entirely  unsuited  for  the  manufacture  of  textiles,  though 
it  is  both  longer  and  stronger  than  Bombax  cotton  or  Kapok. 

This  fibre  is  obtained  from  Asclepias  syriaca  and  A.  incarnata 
or  common  milkweed  or  silkweed.  The  plant  grows  extensively 
in  America.  The  surface  fibre  from  the  seed-pods*  is  used  for 
upholstery  material;  it  has  also  been  used  in  France  for  the 
manufacture  of  woven  fabrics,  being  spun  with  80  per  cent  of 
wool,  and  made  into  a  fabric  known  as  "  silver  cloth." 

The  fibre  of  vegetable  silk  is  quite  brittle  in  nature  and  pos- 
sesses but  little  tensile  strength;  hence  attempts  at  spinning 
it  by  itself  have  not  proved  very  successful.!  Its  chief  physical 
quality  is  its  high  degree  of  lustre  and  softness.  When  examined 
under  the  microscope,  the  fibre  exhibits  thickened  ridges  in 
the  cell-wall  which  serve  to  distinguish  it  from  Bombax  cotton,  f 
Each  fibre  consists  of  a  single  cell,  usually  somewhat  distended 
at  the  base.  It  is  of  a  yellowish- white  color;  the  length  varies 
from  10  to  30  mm.  and  the  diameter  from  0.02  to  0.05  mm. 
As  vegetable  silk  is  somewhat  lignified,  it  may  be  distinguished 
from  true  cotton  by  giving  a  yellowish  brown  coloration  with 
iodin  and  sulphuric  acid,  and  a  yellow  coloration  with  anilin 
sulphate.  Its  micro-chemical  reactions  are  very  similar  to 
Bombax  cotton,  though  with  phloroglucinol  and  hydrochloric 
acid  the  latter  gives  a  dull  violet  coloration,  while  vegetable 
silk  gives  a  bright  red- violet  coloration. 

*  The  same  plant  also  furnishes  a  bast  fibre  which  is  fine,  long,  and  glossy, 
and  said  to  be  equal  in  strength  and  durability  to  hemp. 

t  Vegetable  silk  is  also  unsatisfactory  for  the  manufacture  of  guncotton,  as 
it  burns  too  slowly  and  leaves  too  much  ash. 

J  These  ridges  or  longitudinal  thickenings  occur  from  2-5  times  in  the  fibre; 
in  some  cases  very  distinct,  in  others  scarcely  noticeable.  Owing  to  these  ridges 
the  fibres  appear  to  have  indistinct  longitudinal  striations,  thus  distinguishing 
them  from  other  seed-hairs 


348  THE  TEXTILE  FIBRES 

There  are  several  minor  varieties  of  vegetable  silk,  chief 
among  which  are  the  following:  Asclepias  curassavica  and 
A.  volubilis  from  the  West  Indies  and  South  America;  Calo- 
tropis  gigantea  and  C.  procera  of  southern  Asia  and  Africa; 
several  species  of  Marsdenia  from  India;  Beaumontia  grandiflora 
from  India,  and  different  varieties  of  Strophantus  from  Senegal. 

The  different  varieties  of  vegetable  silk  are  very  difficult 
to  distinguish  from  one  another.  They  all  possess  a  soft  feel 


FIG.  73. — Vegetable  Silk  from  Calotropis  gigantea.  Showing  irregular  thickening 
of  cell-wall  at  A,  and  an  air-bubble  at  B.  Fibres  examined  in  water. 
(Micrograph  by  author.) 

and  a  high  silky  lustre.  In  color  they  vary  from  almost  pure 
white  to  a  slight  orange-yellow.  In  thickness  the  fibres  usually 
vary  from  35  to  60  pi,  though  occasionally  they  may  reach  80  \L. 
In  length  they  vary  from  10  to  50  mm.  The  fibre  has  but  little 
pliability  or  elasticity,  hence  is  very  brittle;  this  is  due  to  the 
very  thin  cell- wall.  All  varieties  exhibit  the  thickened  ridge 
in  the  cell-wall,  which  gives  the  fibre  the  appearance  of  being 


THE  MINOR  SEED-HAIRS  349 

uneven  in  thickness.  In  cross-section,  these  ridges  are  usually 
semi-circular,  though  sometimes  flat  and  broad.  The  cross- 
section  of  the  fibre  itself  is  usually  circular. 

The  seed-hairs  of  the  Beaumontia  grandiflora  furnish 
probably  the  best  variety  of  vegetable  silk,  as  the  fibre  is  not 
only  the  most  lustrous  but  is  also  the  most  purely  white,  and 
furthermore  it  possesses  the  greatest  tensile  strength,  and  the 
fibres  are  easily  separated  from  the  seeds.  The  fibres  are  from 
3  to  4.5  cm.  in  length  and  from  20  to  50  JJL  in  diameter.  The 
cell-wall  is  thin,  being  about  3.9  ^  in  thickness.  At  the  base 
the  fibre  is  somewhat  enlarged  and  the  walls  are  pierced  by 
delicate  elongated  pores  arranged  in  a  row.  The  fibres  of 
Calotropis  gigantea  *  consist  of  thin-walled  colorless  cells  show- 
ing pitted  markings  at  the  base;  they  are  from  2  to  3  cm. 
in  length  and  from  12  to  42  \L  in  diameter;  the  cell-wall  is  from 
1.4  to  4.2  [L  in  thickness. f  At  the  base  the  fibre  is  somewhat 

*  Calotropis  gigantea,  or  giant  asclepias,  also  yields  a  bast  fibre  said  to  be  oJ 
very  superior  quality,  somewhat  resembling  flax  in  appearance  and  of  the  same 
strength.  The  vegetable  silk  enveloping  the  seeds  is  known  in  India  as  madar 
floss.  The  bast  fibre  is  said  to  show  a  high  degree  of  resistance  to  moisture; 
according  to  Spon,  samples  exposed  for  two  hours  to  steam  at  two  atmospheres 
pressure,  boiled  in  water  for  three  hours,  and  again  steamed  for  four  hours,  lost 
only  5.47  per  cent  in  weight,  whereas  flax  under  the  same  conditions  lost  3.50  per 
cent,  manila  hemp  6.07  per  cent,  hemp  6.18  to  8.44  per  cent,  and  coir  8.14  per 
cent.  As  to  the  strength  of  the  fibre,  Dr.  Wrights  tests  give  it  a  breaking  strain 
of  552  pounds  as  compared  with  404  pounds  for  sunn  hemp;  Royle's  tests  give 
it  a  breaking  strain  of  190  pounds  as  compared  with  160  pounds  for  Russian 
hemp  and  190  pounds  for  Jubbulpore  hemp  from  Crotalaria  tenuifolia.  The 
vegetable  silk  from  Calotropis  gigantea  is  known  in  Java  under  the  name  of  kapok, 
though  this  name  is  also  given  to  the  product  of  the  Eriodendron  anfractuosum 
and  Bombax  pentandrum.  The  fibre  is  said  to  have  been  made  into  shawls  and 
handkerchiefs,  but  it  hardly  possesses  sufficient  strength  to  be  spun  alone.  The 
C.  giganlca  is  not  only  a  fibre  plant,  as  it  also  yields  gutta-percha,  varnish,  dye, 
and  medicinal  substances. 

t  The  ridges  in  the  fibre  of  Calotropis  gigantea  are  evident  in  surface  view  only 
after  a  careful  search,  but  in  cross-section  are  more  noticeable.  Here  and  there 
air-bubbles  arj  present  in  the  lumen  and  may  be  recognized  by  their  different 
refractive  power.  Often  one  of  the  ridges  is  more  or  less  crooked.  When  treated 
with  iodin-sulphuric  acid  reagent  of  suitable  strength  the  hairs  exhibit  three 
layers:  (i)  A  pale  yellow  slightly  altered  outer  layer;  (2)  a  greenish  middle 
layer  with  swollen  and  constricted  outer  contour;  and  (3)  a  narrow  inner  tube. 
(Hanausek,  Microscopy  of  Technical  Products,  p.  70.) 


350  THE  TEXTILE   FIBRES 

enlarged  and  flattened,  though  this  formation  is  not  so  per- 
ceptible as  in  the  case  of  Beaumontia  grandi  flora.  The  fibre 
of  Calotropis  gigantea  is  known  in  Venezuela  as  algodon  de  seda. 
It  is  more  yellow  in  color  than  asclepias  cotton.  The  fibres 
from  the  various  species  of  Marsdonia  are  very  uniformly 
cylindrical  and  straight.  In  length  they  vary  from  i  to  2.5  cm. 
and  in  diameter  from  19  to  33  [L.  The  cell- wall  has  an  average 
thickness  of  2.5  [t..  The  fibre  of  Strophantus  differs  somewhat 
from  other  varieties,  in  that  at  the  base  there  occur  pores  in  the 
cell-walls.  This  fibre  is  also  not  so  easily  removed  from  the 
seeds  and  possesses  a  reddish  yellow  color. 

Vegetable  wool  is  a  product  obtained  from  the  green  cones 
of  the  pine  and  fir  by  processes  of  fermentation,  washing,  and 
mechanical  disintegration.  It  is  used  in  mixtures  with  cotton 
and  wool  for  the  production  of  yarns,  and  also  for  the  stuffing 
of  mattresses,  etc.  The  yarns  prepared  from  vegetable  wool 
mixed  with  sheep's  wool  are  used  in  the  manufacture  of  the 
so-called  "hygienic  flannels."  * 

*  These  are  especially  recommended  for  gouty  patients,  as  it  is  claimed  they 
keep  the  body  uniformly  warm  and  protect  it  from  dampness. 


CHAPTER  XV 
ARTIFICIAL  SILKS 

i.  General  Considerations. — Owing  to  the  high  price  and 
value  of  silk  as  a  textile  fibre,  numerous  attempts  have  been 
made  to  produce  an  artificial  filament  resembling  it  in  properties.* 
Several  of  these  processes  have  been  attended  with  a  considerable 
degree  of  success,  and  at  the  present  time  artificial  silk  has 
become  a  commercial  article,!  and  is  used  in  considerable  quan- 
tity by  the  textile  trade.  J  The  varieties  of  these  silks  divide 
themselves  into  the  following  classes  :§ 

*  The  entomologist  Reaumur,  in  the  year  1734,  in  a  memoir  on  the  history  of 
insects,  appears  to  have  been  the  first  to  look  forward  to  the  possible  preparation 
of  silk  by  artificial  means.  It  was  not  until  1884,  however,  that  the  first  commer- 
cial process  for  the  preparation  of  artificial  silk  was  taken  out  in  patent  form  by 
the  Count  Hilaire  de  Chardonnet.  (Eng.  Pat.  6045  of  1885.) 

t  Imports  of  artificial  silk  into  the  United  States  for  the  year  1912  amounted 
to  1,650,685  pounds,  valued  at  $2,647,493.  There  is  one  factory  commercially 
engaged  in  the  manufacture  of  artificial  silk  in  the  United  States  located  at 
Marcus  Hook,  Pa.  Its  present  production  is  about  5000  pounds  per  day,  and  it 
operates  under  the  viscose  method. 

The  price  of  artificial  silk  (120-150  denier)  at  the  present  time  (1912)  averages 
about  $1.75  per  pound. 

t  The  first  attempt  at  the  spinning  of  a  solution  of  collodion  appears  to  have 
been  made  by  Audemars  at  Lausanne  (Eng.  Pat.  283  of  1855).  Further  experi- 
ments were  made  by  Weston  (Eng.  Pat.  of  Sept.  12,  1882)  and  Swan  (Ger.  Pat. 
30291  of  1884)  on  solutions  of  nitrated  cellulose  in  acetic  acid.  Wynne-Powell 
(Eng.  Pat.  of  Dec.  22,  1884)  tried  the  preparation  of  filaments  from  a  solution  of 
cellulose  in  zinc  chloride.  All  of  these  attempts  had  in  view  the  preparation  of 
filaments  for  incandescent  electric  lamps. 

§  Of  the  several  methods  of  making  artificial  silk,  probably  the  only  one 
which  will  survive  in  the  end  is  the  viscose  process.  The  collodion  method  at 
first  enjoyed  great  success  and  factories  working  by  this  process  in  past  years 
have  made  large  profits;  but  owing  to  the  high  cost  of  the  alcohol-ether  solvent 
employed  this  process  cannot  compete  with  the  viscose  method.  The  cupram- 
monium  process  also  seems  to  be  doomed,  for  though  companies  operating  under 
this  process  have  also  made  large  profits,  within  the  past  year  (1911-1912)  they 

351 


352  THE  TEXTILE  FIBRES 

(1)  Pyroxylin  or  collodion  silks,  made    from    a    solution  of 
nitrated  cellulose  in  a  mixture  of  alcohol  and  ether. 

(2)  Cuprammonium  or  cuprate  silks,  made  from  a  solution 
of  cellulose  in  ammoniacal  copper  oxide. 

(3)  Viscose  silks,  made  from  a  solution  of  cellulose  thiocar- 
bonate. 

(4)  Acetate  silks,  made  from  a  solution  of  cellulose  acetate. 

(5)  Gelatin  silks,  made  from  filaments  of  gelatin  rendered 
insoluble  by  treatment  with  formaldehyde. 

With  the  exception  of  the  last  class,  all  of  these  so-called 
silks  are  filaments  of  cellulose,  resolidified  from  various  kinds 
of  solutions,  hence  it  has  been  proposed  to  give  to  these  fibres 
the  general  name  of  lustra-cellulose,  as  one  more  descriptive 
of  their  true  nature. 

From  the  term  "  artificial  silk,"  it  might  be  reasonably 
supposed  that  the  substance  so  designated  is  the  same  in  com- 
position and  nature  as  the  fibre  derived  from  the  silkworm, 
but  made  by  chemical  or  other  artificial  means.  This  is  not 
the  case,  however,  and  the  term  "  artificial  silk  "  is  rather 
a  misleading  one  in  this  sense.  The  name  in  reality  stands 
for  a  fibre  resembling  in  its  lustre  and  general  appearance  the 
true  silk  of  nature;  but  the  identity  goes  no  further  than  this; 
for,  in  its  chemical  composition  and  properties,  artificial  silk 
is  entirely  distinct  from  that  produced  by  the  silkworm.  It 
would  be  better  to  call  the  artificial  product  "  imitation  silk," 
or  give  it  some  name  more  distinctive  of  its  origin  and  true 
nature,  such  as  the  term  "  lustra-cellulose,"  proposed  by  Cross 
and  Bevan.*  The  latter  term  is  especially  adapted  to  the 
product  in  question,  for  the  different  varieties  of  this  fibre 
which  have  acquired  any  degree  of  technical  importance  are 
all  made  from  cellulose  derivatives,  and  their  chief  quality  is 
their  high  degree  of  lustre. 

The  majority  of  the  lustra-cellulose  used  in  trade  at  the 

have  mostly  taken  up  the  viscose  method.  Unless  ^further  methods  are  evolved 
it  is  probable  that  within  a  few  years  the  viscose  method  will  be  the  only  one 
used  for  the  manufacture  of  artificial  silk. 

*  Cross  and  Bevan,  Jour.  Soc.  Chem.  Ind..  1896,  p.  317. 


ARTIFICIAL  SILKS  353 

present  time  falls  under  the  first  three  classes  of  silks.  The 
pyroxylin  silk  represents  the  oldest  method  employed  for 
the  manufacture  of  this  interesting  fibre;  and  there  are  three 
chief  processes  by  which  this  silk  is  made,  known  by  the  names 
of  the  respective  inventors:  Chardonnet,  du  Vivier,  and  Lehner. 
All  of  these  processes  use  a  solution  of  nitrated  cellulose  as  a 
base,  and  employ  the  same  general  mechanical  idea  to  produce 
the  filaments  of  the  fibre,  the  principle  being  to  force  a  solu- 
tion of  nitrated  cellulose  through  a  fine  capillary  tube,  coagulate 
the  thin  stream  of  solution  thus  obtained,  and  finally  denitrate 
and  reel  the  thread  of  filaments  so  obtained.  As  previously 
described  (p.  289),  cellulose,  on  treatment  with  nitric  acid, 
can  be  made  to  yield  a  series  of  nitrated  celluloses,  the  exact 
compound  obtained  being  dependent  upon  the  conditions 
of  treatment. 

2.  Collodion  or  Chardonnet  Silk. — This  is  prepared  from 
nitrated  cellulose  dissolved  under  pressure  in  a  mixture  of 
alcohol  and  ether.*  The  solution  is  coagulated  by  passage 
through  water,  and  is  subsequently  denitrated  by  a  treatment 
with  dilute  nitric  acid,  chloride  of  iron,  and  ammonium  phos- 
phate. It  forms  a  glossy,  flexible  fibre,  possessing  the  peculiar 
feel  and  scroop  of  true  silk. 

When  first  prepared,  pyroxylin  silks  were  very  inflammable, 
which  led  to  their  being  regarded  with  disfavor.  The  processes 
of  denitration,  however,  have  now  rendered  them  even  less 
inflammable  than  ordinary  cotton.  Antiphlogin  is  the  trade- 
name  of  .a  mixture  used  for  the  purpose  of  overcoming  the 

*  Many  attempts  have  been  made  to  reduce  the  cost  of  the  collodion  and  to 
obtain  otner  solvents  for  the  nitrated  cellulose.  Bronnert  in  1895  brought  for- 
ward a  process  of  making  collodion,  based  on  the  solubility  of  tetranitrated 
cellulose  in  alcoholic  solutions  of  certain  salts,  such  as  calcium  chloride,  ammonium 
acetate,  and  ammonium  sulphocyanide.  The  explanations  advanced  for  these 
reactions  are  rather  uncertain.  It  may  be  supposed  that  the  ammonium  acetate 
produces  a  hydrolysis,  the  ammonium  sulphocyanide  a  partial  denitration  of  the 
tetranitrated  cellulose,  and  the  calcium  chloride  an  alcoholic  derivative  of  the 
cellulose,  which  could  well  be  an  ethoxy-derivative,  if  the  opinion  of  Dr.  Bron- 
nert, "that  the  body  designated  by  the  name  of  tetranitrated  cellulose  is  a  tetra- 
nitrated oxycellulose,"  is  correct.  The  different  compounds  thus  formed  would 
be  soluble  in  alcohol.  (See  Bernard,  Mon.  Scientif.,  May,  1905.) 


354 


THE  TEXTILE  FIBRES 


inflammable  nature  of  artificial  silk.  It  consists  of  boric  acid, 
phosphate  of  ammonia,  and  acetic  acid.  Pyroxylin  steeped 
in  this  solution  is  said  to  be  incombustible. 

The  pyroxylin  employed  for  the  production  of  Chard onnet's 
silk  may  be  prepared  from  either  wood-pulp,  cotton,  ramie, 
or  other  source  of  purified  cellulose.*  As  there  are  several 
nitrated  compounds  of  cellulose  soluble  in  the  alcohol-ether 
mixture  (which  is  employed  as  the  pyroxylin  solvent),  and  as  it 


FIG.  74. — Chardonnet  or  Collodion  Silk.     (X35O.) 
(Micrograph  by  author.) 

is  difficult  to  obtain  satisfactory  separations  of  the  individual 
compounds,  it  is  probable  that  the  pyroxylin  contains  penta-, 
tetra-,  tri-,  and  di-nitrated  cellulose,  the  tetra-  and  tri-nitrated 
compounds  probably  occurring  in  larger  amounts.  The  prepara- 

*  The  nitrocellulose  prepared  from  wood  pulp  (sulphite)  gives  a  more  fluid 
solution  when  dissolved  in  the  alcohol-ether  solvent,  but  the  fibre  obtained  after 
spinning  is  inferior  in  tensile  strength,  and  is  said  to  have  less  lustre  and  purity 
of  color  than  filaments  produced  from  cotton  as  the  source  of  cellulose. 


ARTIFICIAL  SILKS 


355 


tion  of  a  pyroxylin,  suitable  for  use  in  the  making  of  Char- 
donnet  silk,  as  prescribed  by  Wyss-Naef,  calls  for  a  nitrating 
mixture  of  15  parts  of  fuming  nitric  acid  (sp.gr.  1.52),  with 
85  parts  of  commercial  sulphuric  acid.  For  4  kilograms  of 
cellulose  about  35  litres  of  this  acid  mixture  are  required,  and 
the  time  of  action  is  from  four  to  six  hours.  Samples  are  examined 
from  time  to  time,  with  the  micro-polariscope  in  order  to  ascer- 
tain the  degree  of  nitration,  and  when  all  the  fibres  appear  of  a 


FIG.  75.— Cross-section  of  Collodion  Silk.     (X25O.) 
(Micrograph  by  author.) 

uniform  bright  blue  color  under  the  polariscope  the  action 
of  the  acid  mixture  is  discontinued.  The  excess  of  acid  is 
removed  from  the  fibre  by  means  of  a  hydraulic  press,  after 
which  the  nitrated  cellulose  is  washed  for  several  hours  with 
water  and  then  pressed  again,  until  the  mass  contains  only 
about  30  per  cent  of  water.  At  first  the  pyroxylin  so  prepared 
was  dried  before  being  dissolved  in  the  alcohol-ether  solvent, 
but  it  was  subsequently  discovered  that  a  better  solution  could 


356  THE  TEXTILE  FIBRES 

be  obtained  by  using  the  pyroxylin  containing  the  amount  of 
water  above  noted.  This  form  of  pyroxylin  has  been  called  by 
Chardonnet  "  pyroxylin  hydrate,"  but  it  is  doubtful  if  the  sub- 
stance is  a  true  hydrate.  However,  it  appears  to  be  about  25 
per  cent  more  soluble  than  the  dry  pyroxylin.  The  solvent 
employed  for  the  pyroxylin  consists  of  a  mixture  of  40  parts  of 
95  per  cent  alcohol  *  with  60  parts  of  ether,  and  100  parts  of 
this  liquid  will  dissolve  about  2$  to  30  parts  of  pyroxylin.  The 
collodion  so  produced  is  filtered  several  times  under  pressure, 
in  order  to  free  it  from  all  non-nitrated  and  undissolved  fibres, 
and  to  obtain  a  perfectly  clear  and  homogeneous  solution. 
This  condition  is  a  very  essential  one  for  the  successful  produc- 
tion of  the  silk,  as  any  irregularity  in  the  solution  would  cause 
a  break  in  the  continuity  of  the  spun  filament  or  a  stoppage 
of  the  machine.  The  pyroxylin  requires  from  15  to  20  hours 
for  complete  solution,  and  that  prepared  from  cotton  requires 
a  longer  time  to  dissolve  than  that  from  wood-pulp.  In  order 
to  properly  filter  the  solution  a  pressure  of  30  to  60  atmospheres 
is  necessary. 

The  next  operation  in  the  manufacture  of  the  silk  is  purely 
a  mechanical  one,  and  yet  one  which  has  required  the  use  of 
considerable  ingenuity  and  skill. t  The  object  is  to  force  the 

*  At  the  Besancon  works,  i  kilo,  of  finished  silk  requires  4-5  litres  of  alcohol 
in  its  manufacture. 

t  An  outline  of  the  methods  employed  in  the  practical  manufacture  of  Char- 
donnet silk  is  as  follows:  A  good  quality  of  wood-pulp  is  carefully  disintegrated 
by  suitable  machines  (resembling  a  carding-machine),  so  as  to  separate  the  indi- 
vidual fibres  as  much  as  possible.  The  bulky,  fleece-like  mass  is  then  dried  by 
steam  heat  at  i4O°-i6o°  C.,  after  which  the  heated  fibres  are  steeped  in  a  mix- 
ture of  concentrated  sulphuric  and  nitric  acids,  as  in  the  general  method  of 
making  guncotton.  After  suitable  treatment  in  the  acids,  the  nitrated  cotton  is 
centrifugated  to  remove  excess  of  acid,  then  washed  until  it  contains  only  about 
10  per  cent  of  acid.  The  product  was  formerly  dried  in  special  drying-rooms, 
where  the  temperature  should  not  be  above  30°  C.,  and  every  precaution  must  be 
taken  to  avoid  explosions.  The  dried  nitrated  cellulose  was  then  dissolved  in  a 
mixture  of  equal  parts  of  alcohol  and  ether,  so  as  to  secure  a  20  per  cent  solution. 
The  resulting  collodion  (as  the  solution  is  now  known)  is  carefully  filtered  through 
silk  sieves  in  such  a  manner  as  to  remove  all  undissolved  fibres  or  other  foreign 
matter.  The  collodion  then  passes  to  the  spinning-machine  where  it  is  forced 
through  tubes  having  nozzles  of  glass  or  platinum  with  fine  orifices.  As  the 
threads  of  collodion  appear  they  come  into  immediate  contact  with  a  fine  stream 


ARTIFICIAL  SILKS  357 

collodion  solution  through  very  fine  capillary  glass  tubes,  so 
that  it  may  be  drawn  thence  as  a  fine  continuous  filament. 
The  collodion  solution  is  quite  viscous,  and  requires  a  pressure 
of  from  40  to  50  atmospheres  to  force  it  through  capillaries  of 
0.08  mm.  diameter.*  The  flow  of  solution  and  pressure  must  be 
so  adjusted  and  capable  of  regulation  as  to  provide  a  uniform 
filament,  and  this  involved  many  mechanical  difficulties,  which 
were  only  overcome  after  long,  experimenting  and  numerous 
failures.  We  will  not,  however,  at  this  point  enter  into  a  con- 
sideration of  the  various  mechanical  devices,  ingenious  though 
they  are,  which  have  been  perfected  for  the  proper  spinning  and 
handling  of  this  artificial  fibre,  f 

The  thread  as  it  emerges  from  the  capillary  tube  is  rapidly 
coagulated  in  the  air  by  the  evaporation  of  the  solvent.  By 
suitable  arrangement  of  a  hood  over  the  machine  and  condensing 
chambers  in  connection  therewith,  a  large  portion  of  the  mixed 
volatile  vapors  of  the  alcohol  and  ether  employed  as  the  solvent 
are  condensed  and  collected,  thus  effecting  a  considerable 
saving  in  the  amount  of  solvent  required,  and  also  minimizing 
the  danger  of  explosions  occurring.  Several  of  the  individual 
filaments  are  brought  together  into  a  single  thread  and  wound 

of  water,  which  removes  the  solvent  and  coagulates  the  cellulose  compound. 
Recently,  however,  methods  have  been  devised  to  spin  the  filaments  dry  instead 
of  under  water.  Several  of  the  fine  threads  are  united  and  are  wound  on  bobbins 
and  into  suitable  hanks.  The  silk  is  then  denitrated  by  treatment  with  a  warm 
solution  (5  to  20  per  cent)  of  ammonium  sulphide,  after  which  the  hanks  are 
washed  and  slightly  acidified  in  order  to  remove  all  the  ammonium  compounds. 
The  process  of  denitration  causes  the  silk  to  lose  about  40  per  cent  in  weight, 
though  this  is  usually  replaced  in  part  by  proper  impregnation  with  solutions 
of  metallic  salts,  which  a'so  have  the  effect  of  making  the  silk  fireproof.  In  the 
manufacture  of  collodion  silk,  an  important  factor  is  the  recovery  of  the  solvent 
from  the  wash- waters;  owing  to  the  extreme  volatility  of  the  ether  this  is  by 
no  means  an  easy  task. 

*  As  the  solutions  of  nitrated  cellulose  possess  great  viscosity,  it  is  difficult 
to  prepare  a  very  concentrated  solution.  The  addition  of  formaldehyde  or 
benzol,  however,  to  the  ordinary  solvents,  will  increase  the  dissolving  capacity 
considerably,  and  also  give  a  more  mobile  solution.  Epichlor-  and  dichlorhydrins 
also  act  as  excellent  solvents  for  nitrated  cellulose,  being  capable  of  dissolving  it 
in  any  proportion. 

t  See  Silvern,  Die  kitnstliche  Seidc,  Berlin,  1912,  and  Williams,  La  Sole  Arti- 
ficielle,  Paris,  1902. 


358  THE  TEXTILE  FIBRES 

on  spools  in  the  manner  of  ordinary  silk.  In  this  operation 
a  certain  amount  of  adhesion  takes  place  between  the  separate 
filaments,  which  considerably  enhances  the  ultimate  strength 
of  the  finished  thread.  The  thread  in  this  form  now  consists 
of  pyroxylin  or  nitrated  cellulose,  and  is  highly  inflammable 
and  otherwise  unsuitable  for  use  in  textile  fibres.  The  next 
operation  through  which  it  passes  is  one  for  the  purpose  of 
denitrating  the  cellulose,  in  order  that  the  fibre  may  ultimately 
consist  of  what  might  be  termed  "  regenerated  "  cellulose,  the 
exact  chemical  nature  of  which  it  is  not  possible  to  state 
definitely,  though  it  is  evidently  some  form  of  cellulose.*  The 
denitration  is  accomplished  by  passing  the  pyroxylin  threads 
through  a  bath  of  ammonium  sulphide,  though  other  alkaline 
sulphides,  and  various  other  compounds  also,  will  effect  the  same 
result,  f  The  silk  in  this  condition  has  a  rather  yellow  color, 
which,  however,  may  be  bleached  out  in  the  usual  manner 
with  a  solution  of  chloride  of  lime  or  sodium  hypochlorite.J 

*  According  to  Dulitz  (Chem.  Zeit.,  1910,  p.  989)  it  is  not  possible  to  obtain 
a  product  absolutely  free  from  all  traces  of  nitrogen  without  the  destruction  of 
the  filament.  For  practical  purposes  the  denitrated  silk  contains  about  0.05  per 
cent  of  nitrogen.  The  uniformity  of  denitration  is  very  important,  and  is  one 
of  the  chief  difficulties  in  the  manufacture  of  collodion  silk.  According  to  Gorrand 
(Fr.  Patent  354,424  of  1905),  the  addition  of  a  small  quantity  of  acetk  acid  to 
the  collodion  solution  before  spinning  accelerates  the  subsequent  denitration 
process  with  ammonium  sulphide. 

f  Pyroxylin  silk  loses  about  8  per  cent  in  strength  by  denitration.  It  is 
probable  that  some  oxy cellulose  is  formed  in  this  process. 

|  For  the  bleaching  of  Chardonnet  silk  the  proportions  are  as  follows: 

Pounds. 

Artificial  silk 16 

Bleaching  powder 4 

Hydrochloric  acid 8 

The  bleached  skeins  are  washed  in  cold  water  to  remove  all  trace  of  chlorine, 
then  softened  with  Turkey-red  oil. 

Dulitz  (Chem.  Zeit.,  1911,  p.  189)  states  that  in  the  bleaching  of  collodion 
silk  the  use  of  bleaching  powder  is  now  almost  entirely  discarded  since  it  injuri- 
ously affects  the  strength  of  the  fibre  and  causes  subsequent  discoloration. 
Various  peroxides  and  per-salts  have  been  tried  but  owing  to  their  high  cost,  and 
to  the  fact  that  they  tend  to  produce  a  harsh  fibre  have  not  been  generally 
adopted.  Sodium  hypochlorite  solutions  having  a  concentration  of  0.5  gram 
of  active  chlorin  per  litre  are  now  in  general  use,  often  with  the  addition  of 


ARTIFICIAL  SILKS  359 

The  fibre,  as  finally  obtained,  possesses  a  very  high  lustre, 
though  it  is  somewhat  metallic  in  appearance;  it  has  consider- 
able tensile  strength,  though  in  this  respect,  as  also  in  elasticity, 
it  is  considerably  below  true  silk.  The  fibre  is  also  rather  harsh 
and  brittle,  and  does  not  possess  the  softness  and  resiliency  of 
natural  silk.* 

3.  Lehner's    Silk. — Though    this  is   also    a  collodion  silk, 
the   process   of    its    manufacture  differs  in  some  details  from 
that  of  the  Chardonnet  process.     While  in  the  latter  the  con- 
centration of  the  collodion  was  as  high  as  20  per  cent,  Lehner 
used  only   10  per  cent  solutions.     The  pressure  required  for 
spinning  was  also  considerably  reduced  by  lowering  the  vis- 
cosity of  the  solution  by  the  addition  of  a  small  amount  of 
sulphuric   acid.     Lehner   also   attempted    the   use   of   natural 
silk  waste  dissolved  in  glacial  acetic  acid.f 

4.  Other    Collodion   Silks. — There  have  been  a  variety  of 
modifications  in  Chardonnet's  method  for  the  preparation  of 
the  collodion  solution  and  the  details  of  spinning  the  filament. { 

sodium  carbonate  or  Turkey-red  oil.  Hydrochloric  acid  is  mostly  used  for  sour- 
ing as  it  is  most  easily  removed  by  washing  and  gives  a  softer  thread.  Treat- 
ment with  soap  or  Turkey-red  oil,  without  washing,  before  immersing  in  the 
bleach  liquor  is  said  to  be  advantageous. 

*  See  Matthews,  Jour.  Soc.  Chem.  Ind.,  1904,  p.  176. 

t  Lehner's  silk  is  now  produced  by  much  the  same  means  as  that  of  Char- 
donnet, and  the  fibre  is  very  similar  to  that  of  the  latter.  Lehner  at  first  attempted 
to  obtain  a  fibre  from  a  mixture  of  pyroxylin  solution  with  various  vegetable  gums 
and  oils,  with  solutions  of  cotton  in  copper-ammonium  sulphate,  and  even  with 
solutions  of  waste  silk  itself.  None  of  these,  however,  proved  a  success,  and  he 
reverted  to  the  more  simple  solution  of  pyroxylin  in  combination  with  a  drying 
oil.  He  also  discovered  that  the  fluidity  of  the  collodion  could  be  materially 
enhanced  by  the  addition  of  sulphuric  acid,  and  consequently  he  was  able  to  work 
his  solution  under  much  less  pressure  than  Chardonnet. 

t  Besides  the  processes  previously  given  of  obtaining  collodion  silk,  there  are 
other  methods  for  the  manufacture  of  this  artificial  product.  Langhaus  employs 
as  a  raw  material  a  preparation  from  cellulose  and  sulphuric  acid.  This  process 
consists  in  dissolving  cellulose  in  a  mixture  of  concentrated  sulphuric  acid  and 
phosphoric  acid,  and  treating  the  syrup  so  obtained  with  glyceric  ether  or  ethyl 
ether.  The  silk  obtained  by  this  process  is  not  of  good  quality,  and  the  solution 
is  not  very  stable,  as  it  soon  precipitates  more  or  less  altered  cellulose.  Cadarat 
uses  nitrated  cellulose,  dissolving  it  in  a  very  complex  mixture  of  glacial  acetic 
acid,  ether,  acetone,  alcohol,  toluol,  camphor,  and  castor-oil.  This  forms  a 
plastic  mass  which  is  treated  with  some  proteid  substance,  such  as  gelatin  or  albu- 


360  THE  TEXTILE   FIBRES 

Du  Vivier's  silk,  known  also  as  "  Sole  de  France"  was  prepared 
from  a  solution  of  nitrated  cellulose  in  glacial  acetic  acid  to 
which  gelatin  was  added.  Substances  such  as  a  solution  of 
gutta  percha  in  carbon  disulphide,  glycerin  and  castor  oil  were 
also  added.  A  coagulating  bath  of  sodium  bisulphite  was 
employed  and  the  silk  was  subsequently  denitrated  in  the 
form  of  hanks.  Du  Vivier's  silk,  however,  did  not  pass  beyond 
the  experimental  stage,  and  is  no  longer  on  the  market. 

Crespin  *  has  endeavored  to  minimize  the  amount  of  solvent 
by  dissolving  the  nitrated  cellulose  in  a  mixture  of  methyl  and 
ethyl  alcohols  and  ether,  to  which  solution  is  also  added  some 
glycerine  and  castor  oil.  Cazeneuve  t  has  claimed  the  use 
of  acetone  as  a  solvent  for  the  nitrated  cellulose;  but  a  filament 
spun  from  an  acetone  solution  is  opaque  and  brittle.  The 
suggested  improvements  and  modification  of  processes  for  the 
preparation  of  collodion  silk  have  been  legion,  as  evidenced 
by  the  large  number  of  patents  taken  out  in  this  field;  most  of 
these,  however,  are  worthless  or  impracticable.  % 

5.  Cuprammonium  Silk. — Lustra-cellulose  threads  are  also 
prepared  from  a  solution  of  cellulose  in  ammoniacal  copper 
oxide  solution  (Schweitzer's  reagent). §  Pauly's  process  in 
brief  was  as  follows:  The  copper  solution  is  first  prepared  by 
treating  copper  turnings  with  ammonia  in  the  presence  of 
lactic  acid  at  a  temperature  of  4°  to  6°  C.  At  the  end  of  about 
ten  days  the  intense  blue  solution  of  ammoniacal  copper  oxide 

min  dissolved  in  glacial  acetic  acid.  After  spinning  the  fibres  are  treated  with 
tannin  in  order  to  render  them  elastic. 

*  U.  S.  Patent  820,351  of  1906. 

f  Fr.  Patent  346,693  of  1904. 

%  For  a  complete  presentation  of  this  patent  literature  consult  Siivern,  Die 
kunstliche  Se-ide,  1912.  Also  see  Worden,  Nitrocellulose  Industry,  1911 ,  pp.  454-565. 

§  Weston,  in  1884,  used  this  solution  for  the  making  of  incandescent-lamp 
filaments;  Despeissis,  in  1890,  first  thought  of  applying  it  to  the  preparation  of 
artificial  silks.  Fremery  and  Urban,  in  1897,  under  the  name  of  Pauly,  patented 
the  first  practical  process  for  the  manufacture  of  the  fibre  (Eng.  Pat.  28,631  of 
1897).  This  silk  is  now  made  in  considerable  quantity  by  the  Vereinigte  Glanz- 
stoff-Fabriken  Actiengesellschaft  of  Elberfeld,  who  have  factories  at  Oberbruch 
and  Niedermorschweiler.  The  product  is  known  as  Glanzstojf,  Cuprate,  Pauly's 
silk  or  Parisian  artificial  silk. 


ARTIFICIAL  SILKS  361 

is  ready  for  use.     The  next  step  is  to  obtain  mercerized  cellulose 

(cellulose  hydrate),*  which  is  done   by   mixing    100   parts   of 

•cotton  with   1000  parts  of  a  solution  containing  30  parts  of 

sodium     carbonate    and    50     parts    of     caustic    soda.f     This 


FIG.  76. — Cuprammonium  or  Glanzstoff  Silk.     (X35o.) 
(Micrograph  by  author.) 

*  Ordinary  cellulose  dissolves  but  very  slowly  in  Schweitzer's  reagent,  and 
moreover,  the  solution  is  always  accompanied  by  oxidation  which  changes  the 
cellulose  molecule  so  that  it  is  not  fit  to  spin.  Bronnert  first  proposed  the  use  of 
cellulose  hydrate,  and  so  made  the  method  of  practical  value. 

f  Friederich  prepares  stable  solutions  of  cuprammonium  cellulose  by  dis- 
solving 4  kilos,  of  copper  sulphate,  CuSO4,  in  li  litres  of  water,  and  adding  2.41 
litres  of  caustic  soda  of  38°  Be.  and  i  litre  of  water.  He  then  adds  20  grams 
of  dextrin,  which  are  taken  up  by  the  hydrate  of  copper  which  is  formed,  and 
200  grams  of  cut-up  cotton  fibre.  The  insoluble  cellulose  pulp  impregnated  with 
the  hydrate  of  copper  is  separated  by  the  aid  of  a  filter-press,  and  is  mixed  with 
i  litre  of  concentrated  ammonia.  In  a  short  time  there  is  produced  a  homo- 
geneous solution  containing  8  to  9  per  cent  of  cellulose  which  is  very  stable  owing 
to  the  presence  of  dextrin.  Mannite,  glycerin,  and  crude  cane  molasses  may  also 
be  used  in  place  of  the  dextrin.  This  solution  may  be  heated  to  30°  to  40°  C. 
without  danger  of  decomposition.  (See  Fr.  Pat.  404,372;  also  418,182  and 


362 


THE  TEXTILE  FIBRES 


mixture  is  heated  for  3^  hours  in  a  closed  vessel  under  a  pres- 
sure of  2\  atmospheres.  The  mercerized  cotton  thus  obtained 
is  washed,  dried,  bleached  with  chloride  of  lime,  washed  and 
again  dried;  after  which  it  is  dissolved  in  the  ammoniacal  copper 
oxide  solution.*  The  solution  (containing  7  to  8  per  cent  of 


FIG.  77. — Cross-sections  of  Cuprate  Silk. 
(Micrograph  by  author.) 


(X2So.) 


405,571.)     Pawlikowski  prepares  cuprammonium  solutions  of  cellulose  (see  Fr. 
Pat.  403,448)  by  the  aid  of  copper  oxychloride,  which  renders  unnecessary  the 
previous  hydration  of  the  cotton  with  caustic  soda,  that  is  to  say,  mercerizing 
and  bleaching.     The  following  proportions  are  recommended  for  use: 
100  grams  of  pure  cotton  linters; 

90      "      copper  oxychloride  (containing  44  to  57  per  cent  of  copper); 
900  c.c.  of  ammonia  water  (0.93). 

Friederich  (Fr.  Pat.  357,171)  has  suggested  the  use  of  alkylamines  to  replace 
the  ammonia  in  the  preparation  of  the  copper-cellulose  solutions. 

*  The  passage  of  an  electric  current  through  the  liquid,  or  the  presence  of  an 
electronegative  metal  in  contact  with  the  copper,  is  said  to  facilitate  the  solution 
of  the  cellulose.  The  operation  is  carried  out  cold,  and  is  hastened  by  the  presence 
of  an  excess  of  free  copper  hydrate  or  carbonate.  The  addition  of  caustic  soda 
to  the  ammoniacal  solution  of  copper  is  also  said  to  facilitate  the  preparation  of 


ARTIFICIAL  SILKS  363 

mercerized  cotton)  is  filtered,  settled,  and  then  spun  through 
capillary  tubes  under  a  pressure  of  2  to  4  atmospheres.  The 
thread  is  coagulated  by  passing  through  a  bath  of  acetic  acid 
or  one  containing  30  to  65  per  cent  of  sulphuric  acid,  at  the 
ordinary  temperature.* 

In  Linkmeyer's  process  the  cuprammonium  solution  of 
cellulose  is  coagulated  by  passage  through  a  solution  of  caustic 
soda.  This  forms  a  copper-alkali-cellulose.  This  compound 
is  then  dissociated  by  treatment  with  water  and  the  precipitated 
copper  oxide  is  removed  from  the  fibre  by  dilute  acid. 

In  Thiele's  process  (cellulo  silk)  a  concentrated  cupram- 
monium solution  of  cellulose  is  pased  through  wide  openings 
into  a  liquid  (NaOH  of  39°  Be)  which  slowly  coagulates  the 
cellulose.  The  threads  are  drawn  out  to  extreme  fineness  by 
means  of  a  glass  roller  revolving  in  acid. 

The  cuprammonium  solutions  of  cellulose  are  rather  unstable, 
being  rapidly  precipitated  by  the  addition  of  neutral  dehydrat- 
ing agents  such  as  alcohol,  sodium  chloride,  etc.  A  flocculent 
jelly  consisting  of  cellulose  hydrate  is  formed,  t 

When  a  cuprammonium  solution  of  cellulose  is  treated 
with  zinc,  the  copper  is  precipitated  and  there  is  formed  a  color- 
less solution  of  zinc  ammonium  cellulose. 

For  the  successful  operation  of  the  cuprammonium  process 

more  concentrated  solutions  of  cellulose,  probably  owing  to  the  simultaneous 
hydration  of  the  fibre.  The  cuprammonium  solution  of  cellulose  may  be  con- 
centrated by  evaporating  from  it  a  large  part  of  the  ammonia  by  a  current  of 
air.  In  this  manner  a  solution  may  be  obtained  containing  10  per  cent  of  cellulose. 

*  The  cuprammonium  filament  may  also  be  coagulated  by  passing  through  a 
40  per  cent  solution  of  caustic  soda.  The  coagulated  thread  is  washed  with  water, 
and  the  copper  removed  by  treatment  with  an  acid  bath  combined  with  the 
action  of  an  electric  current. 

t  Berl  (Chem.  Zeit.,  1910,  p.  532)  has  investigated  the  formation  and  properties 
of  cuprammonium  solutions  of  cellulose.  The  viscosity  of  the  solution  depends 
on  the  previous  preparation  of  the  cellulose,  the  amount  dissolved,  and  the  age 
of  the  solution.  The  solution  will  rapidly  absorb  oxygen,  leading  to  the  formation 
of  oxycellulose,  which  has  little  value  for  spinning.  The  formation  of  cuprammon- 
ium cellulose  is  said  to  be  a  colloidal  phenomenon,  the  colloidal  portion  of  the 
cuprammonium  hydrate  joining  the  cellulose  to  form  an  adsorption  product 
soluble  in  ammonia.  Bronnert  (Rev.  Gen.  Mat.  Col.,  1900,  p.  267)  notes  that  hydro- 
cellulose  is  practically  insoluble  in  the  cuprammonium  liquor. 


364  THE  TEXTILE   FIBRES 

a  uniformly  low  temperature  is  required  and  a  certain  fixed 
ration  between  the  amounts  of  copper,  ammonia,  and  cellulose 
employed. 

6.  Use    of   Other    Cellulose    Solutions.— Silk-like    filaments 
may  be  obtained  from  a  solution  of  cellulose  in  zinc  chloride.* 
The  liquid  may  be  easily  spun,  but  the  thread  which  is  formed 
is  too  weak  to  be  employed  as  a  substitute  for  silk.     The  solu- 
tion is  principally  used  for  the  manufacture  of  filaments  for 
incandescent  electric  lamps.     A  better  solution  is  obtained  by 
using  alkali-cellulose  in  place  of  cellulose  (Bronnert). 

7.  Viscose  Silk. — This  is  prepared  from  solutions  of  cellu- 
lose thiocarbonate.f     It  has  been  made  with  some  degree  of 
commercial  success  in  the  United  States  and  Europe.     It  is 
principally  made  in  coarse  numbers,  and  is  used  as  an  artificial 
horsehair.     Finer   numbers  of   considerable  softness  have  also 
been  made,  for  use  in  braids,  passementerie,  etc. 

Viscose  itself  is  prepared  by  the  action  of  caustic  alkali  and 
carbon  disulphide  on  mercerized  cellulose,  J  a  gelatinous  mass 
being  obtained  which  is  readily  soluble  in  water,  giving  a  yellowish 
and  very  viscous  solution.  Viscose  is  an  alkaline  xanthate  of 
cellulose,  and  its  industrial  manufacture  is  carried  out  in  the 
following  general  manner:  Sheets  of  pure  bleached  sulphite 
wood-pulp  are  ground  up  with  solid  caustic  soda  in  a  circular 
edge-roller  mill  until  a  finely  divided  crumb-like  mass  is  obtained. 
The  product  in  this  form  is  known  as  "  crumbs,"  and  consists 
of  alkali-cellulose.  The  excess  of  moisture  is  then  pressed  out,§ 

*  Dreaper  and  Thomson  (Eng.  Pat.  17,901  of  1898).  The  solution  of  cellulose 
in  zinc  chloride  is  forced  through  jets  into  alcohol  or  acetone,  which  coagulates 
the  cellulose. 

f  Stearn,  Eng.  Pat.  1020  of  1898. 

J  In  practice  there  are  employed  one  molecule  of  cellulose,  two  molecules  of 
caustic  soda,  one  molecule  of  carbon  disulphide,  and  30-40  molecules  of  water. 
The  corresponding  molecular  weights  of  these  ingredients  are  as  follows: 

1  cellulose,  C6H10O5 165 

2  caustic  soda,  2NaOH 80 

i  carbon  disulphide,  CS% 76 

30-40  water,  30-40  H2O 540-720 

§  This  operation  should  be  so  conducted  as  to  leave  for  300  parts  of  alkali- 


ARTIFICIAL  SILKS  365 

and  the  material  is  allowed  to  lie  for  some  time.  This  alkali- 
cellulose  is  then  placed  in  an  iron  vat  provided  with  a  rotary 
stirrer,  where  it  is  treated  with  carbon  disulphide.*  The  result- 
ing mass  is  translucent  and  gelatinous  in  appearance  and  of  a 
clear  brown  color,  f  and  is  known  by  the  name  of  viscose. 
Immediately  after  its  formation,  the  viscose  is  dissolved  in 
water  and  then  filtered  in  order  to  remove  any  cellulose  fibre 
which  may  not  have  undergone  chemical  transformation. 
For  the  successful  preparation  of  artificial  silk  it  is  necessary 
that  the  filtering  should  be  as  perfect  as  possible,  for  the  occur- 
rence of  any  fibres  in  the  solution  will  cause  stoppages  of  the 
spinnerets  and  consequently  breaks  in  the  filaments.  After 
filtering  the  viscose  solution  is  thoroughly  mixed.  The  freshly 
prepared  solutions  of  viscose  are  very  thick  and  viscous,  but 
when  allowed  to  "  ripen  "  for  some  time  they  become  more 
fluid  and  homogeneous.  When  the  desired  degree  of  fluidity  has 
been  attained  (which  is  indicated  by  means  of  a  viscosimeter),t 
the  viscose  solution  is  run  into  suitable  reservoirs,  in  which  it 
is  maintained  at  a  temperature  of  32°  F.  Previous  to  passing 
into  the  spinning-machines,  the  solution  is  filtered  a  second  time, 
after  which  it  is  run  into  an  apparatus  where  it  is  subjected  to 
high  pressure  for  the  purpose  of  forcing  out  all  air-bubbles  which 
are  liable  to  be  retained  due  to  the  viscous  nature  of  the  solu- 
tion. This  latter  treatment  is  very  essential,  as  the  presence 
of  air-bubbles  would  interfere  very  materially  with  the  regularity 
of  the  spun  fibre.  The  viscose  solution  then  goes  into  an 
apparatus  which  may  be  called  a  spinning-frame.  This  con- 
cellulose,  ioo  parts  of  cellulose  and  200  parts  of  caustic  soda  of  26°  Be.  That  is 
to  say,  the  proportion  should  be  about  ioo  parts  of  dry  cellulose  to  48.5  parts  of 
caustic  soda  (NaOH).  The  caustic  soda  should  be  pure  and  free  from  carbonate 
in  order  to  obtain  good  results. 

*  For  each  ioo  parts  of  cellulose  there  should  be  used  34.5  parts  of  carbon 
disulphide. 

t  The  viscose  prepared  from  cotton  is  of  a  brownish  color,  while  that  prepared 
from  wood-pulp  is  more  of  an  orange  color. 

t  Viscose  solutions  are  also  tested  for  degree  of  ripening  by  treatment  with 
a  40  per  cent  solution  of  acetic  acid.  If  the  viscose  is  not  sufficiently  matured 
it  will  dissolve,  but  if  the  solution  has  arrived  at  its  proper  condition  the  viscose 
will  gradually  coagulate  and  give  a  solid  and  coherent  filament. 


366 


THE   TEXTILE  FIBRES 


sists  of  a  double  series  of  small  pumps,  which  force  the  solution 
through  platinum  spinnerets  pierced  with  very  fine  openings, 
the  number  of  which  varies  with  the  size  of  the  thread  it  is 
desired  to  produce.  The  production,  therefore,  is  proportional 
to  the  number  of  orifices  in  use;  the  normal  number  being 
about  eighteen  orifices  per  thread,  while  each  orifice  corresponds 
to  a  daily  production  of  about  28  grams  (about  one  ounce). 
Each  spinneret  and  tube  which  carries  it  are  immersed  in  a  con- 


FIG.  78.— Viscose  Silk.     (X35O.) 
(Micrograph  by  author.) 

centrated  solution  of  ammonium  sulphate,  or  dilute  sulphuric 
acid,  for  the  purpose  of  coagulating  the  liquid  jet  coming  from 
the  spinneret  by  bringing  it  into  immediate  contact  with  the 
solution.  The  different  filaments  forming  the  threads  are  at 
the  same  time  united  into  one  single  fibre,  and  these  are  car- 
ried into  a  solution  of  ferrous  sulphate  (copperas)  in  order  to 
remove  all  residual  matter  left  on  the  fibre  from  the  first  bath. 
The  threads  then  pass  into  a  turbine  bobbin,  which  collects 


ARTIFICIAL  SILKS 


367 


them  into  skeins,  and  at  the  same  time  gives  the  thread  the 
desired  degree  of  twist.  The  fibre,  in  the  form  of  hanks,  is 
then  steeped  in  an  acid  solution  for  the  purpose  of  neutralizing 
any  alkali  left  in  the  filaments,  the  excess  of  acid  being  after- 
ward removed  by  washing  in  water.  Residual  sulphur  com- 
pounds are  removed  by  treatment  with  a  solution  of  sodium 
sulphide.  Sodium  bisulphate  as  well  as  sodium  bisulphite  with 
aluminium  sulphate  are  also  used.  The  fibre  at  this  stage 


FIG.  79. — Cross-sections  of  Viscose  Silk.     (X25O.) 
(Micrograph  by  author.) 

has  a  rather  pronounced  yellow  color,  which  is  removed  by 
bleaching  with  chloride  of  lime  or  better  with  a  neutral  solution 
of  sodium  hypochlorite.  Viscose  silk  has  a  fine  glossy  appear- 
ance, and  possesses  a  tensile  strength  about  equal  to  that  of 
pyroxylin  silk;  like  the  latter,  however,  it  is  also  weakened 
when  moistened  with  water. 

The  amount  of  free  alkali  and  combined  alkali  present  in 
viscose   may   be   determined   quantitatively   through   the   dif- 


368  THE  TEXTILE  FIBRES 

ference  in  the  action  of  organic  and  mineral  acids  on  viscose. 
It  is  possible  to  treat  a  solution  of  viscose  (cellulose  xanthate) 
with  an  excess  of  acetic  acid  in  order  to  neutralize  the  free 
alkali  without  attacking  the  alkali  combined  with  the  cellulose 
group.  If  the  viscose,  however,  is  treated  with  dilute  sul- 
phuric acid  and  boiled,  the  xanthate  is  decomposed,  and  thus 
the  total  alkali  may  be  obtained.  The  difference  in  the  two 
results  gives  the  combined  alkali.* 

The  amount  of  sulphur  in  viscose  is  determined  by  first 
oxidizing  to  sulphate  by  treatment  with  an  excess  of  sodium 
hypochlorite,  then  precipitating  and  determining  by  the  usual 
gravimetric  method  as  barium  sulphate. 

The  determination  of  the  viscosity  of  viscose  solutions  is 
an  important  analytical  factor.  This  test  may  be  made  by  one 
of  several  methods:  (a)  The  solution  of  viscose  is  placed  in  a 
30  c.c.  Mohr's  burette  graduated  in  i/io  c.c.,  and  having  an 
orifice  i  mm.  in  diameter.  The  time  required  for  30  c.c.  of 
the  solution  to  run  from  the  burette  is  noted.  If  this  time  is 
the  same  for  different  samples  from  the  solution  it  indicates 
the  viscose  is  well-ripened  and  homogeneous,  (b]  Another 
method  is  to  employ  a  glass  tube  3  cm.  in  diameter  with  two 
marks  50  cm.  apart.  The  tube  is  filled  with  the  viscose  solution 
to  the  upper  mark  and  placed  in  a  vertical  position.  A  small 
nickel  ball  5  mm.  in  diameter  is  then  introduced,  and  the  time 
required  for  it  to  fall  between  the  two  divisions  is  noted.  A 
solution  in  proper  condition  for  spinning,  when  at  a  temperature 
of  70°  F.,  should  show  16-17  seconds  for  the  fall  of  the  nickel 

*  The  analysis  is  carried  out  as  follows:  50  grams  of  the  viscose  are  dissolved 
in  water  and  made  up  to  a  volume  of  500  c.c.  To  100  c.c.  of  this  solution  is  added 
a  definite  volume  of  semi-normal  acetic  acid  in  sufficient  excess  to  cause  total 
precipitation  of  the  viscose.  The  precipitate  is  filtered  off  and  washed  with 
saturated  brine.  In  the  filtrate  so  obtained  the  excess  of  acetic  acid  is  deter- 
•mined  by  titration  with  semi-normal  caustic  soda,  using  phenolphthalein  as 
indicator.  To  a  second  100  c.c.  sample  of  the  viscose  solution  is  added  50  c.c. 
(or  more  if  necessary)  of  normal  sulphuric  acid.  The  solution  is  brought  to  boil- 
ing, the  precipitate  is  filtered  off  and  washed.  In  the  filtrate  the  excess  of  sul- 
phuric acid  is  titrated  with  normal  caustic  soda  using  methyl  orange  as  indicator. 
The  acid  neutralized  by  the  viscose  gives  the  total  alkali,  and  the  difference 
between  the  first  result  and  this  latter  gives  the  alkali  combined  as  xanthate. 


ARTIFICIAL   SILKS 


369 


ball,  (c)  Boverton  Redwood's  or  Engler's  viscosimeter  may  be 
used.  In  these  a  definite  volume  of  the  solution  to  be  tested 
is  allowed  to  flow  through  a  small  opening  and  the  time  compared 
with  that  required  for  water,  (d)  In  Doolittle's  apparatus 
the  viscosity  is  determined  by  the  friction  against  a  rotating 
weight  moving  in  the  liquid,  the  motion  being  imparted  to  the 
weight  by  the  torsional  twist  of  the  suspending  wire.  -  * 

As  employed  for  purposes  of  spinning,  the  viscose  solution 
should  contain  about  6  to  7  per  cent  of  cellulose  and  8  per  cent 
of  caustic  soda.  In  ripening  or  aging  the  viscose  solution  a 
temperature  of  about  70°  F.,  is  maintained  until  the  liquid 
acquires  the  proper  fluidity.  The  ripening  process  must  then 
be  stopped  at  the  proper  point  by  cooling  the  solution  to  23° 
F.  by  refrigeration. 

A  viscose  solution  will  begin  to  coagulate  7-8  days  after 
its  preparation.  The  coagulum  will  at  first  occupy  the  entire 
volume  of  the  solution,  but  soon  contracts  little  by  little. 
After  47  days  the  shrunken  coagulum  of  cellulose  hydrate  occu- 
pies only  30  per  cent  of  the  original  volume.  It  then  forms  a 
rather  hard  mass,  and  is  known  as  viscolith. 

When  viscose  silk  is  treated  with  formaldehyde  in  the  pres- 
ence of  acids  and  dehydrating  agents  it  is  said  that  the  thread 
acquires  a  greater  resistance  to  moisture,  and  consequently 
shows  less  loss  of  tensile  strength  when  wetted.*  The  artificial 
silk  is  placed  in  a  bath  containing  i-io  parts  of  formaldehyde 
and  90-99  parts  of  acetic  acid  (40  per  cent).  This  process  is 
known  as  "  sthenosage  "  or  strengthening,  f 

*  Eschalier,  Fr.  Pat.  374,724. 

f  Cross  and  Bevan  (Jour.  Soc.  Chera.  Ind.,  1908,  p.  1189),  give  the  following 
table  showing  the  effect  of  the  sthenosage  process  on  the  quality  of  artificial  silk: 


Breaking  Strain, 
Grams  per  Unit 
Denier. 

Elasticity. 
Per  Cent. 

Air-dry. 

Wetted. 

Air-dry. 

Wetted. 

Artificial 
and  vi 
Sthenose 

silk  of  collodion,  cuprammonium 
scose  methods  

1-25 
1.6 

0-37 
i.i 

12.  2 

7-8 

9.0 
7.6 

products  

370  THE  TEXTILE  FIBRES 

The  necessity  of  "  aging  "  or  "  ripening  "  viscose  solutions 
previous  to  spinning  has  been  obviated  by  the  addition  of  a 
neutral  salt*  (such  as  sodium  sulphite  or  sodium  silicate)  to 
the  solvent  for  the  cellulose  xanthate  before  the  latter  is  added. 
This  imparts  to  the  viscose  solution  the  property  of  immediately 
coagulating  when  ejected  into  a  weak  acid  bath. 

By  coating  a  cotton  thread  with  a  solution  of  viscose  an 
imitation  horsehair  can  be  obtained.  This  product  is  known 
under  the  name  of  "  viscelline  "  yarn. 

8.  Acetate  Silk. — The  acetate  of  cellulose*  (see  p.  280)  has 
also  been  used  as  a  basis  for  the  manufacture  of  artificial  silk.f 
It  is  dissolved  in  a  suitable  solvent!  and  spun  in  the  same  man- 
ner as  collodion  silk,  the  thread  being  coagulated  by  passing 
through  a  bath  of  water.  With  collodion  silk  the  weight  of  the 
product  obtained  (after  denitration)  is  scarcely  equal  to  that 


*  Ernst  (U.  S.  Pat.  863,793  of  1907).  It  is  here  pointed  out  that  if  the  viscose 
formed  by  dissolving  the  cellulose  xanthate  in  a  suitable  solvent  be  allowed 
to  stand  or  "  age  "  for  a  sufficient  length  of  time,  it  will  of  itself  change  or  coagulate; 
hence  it  will  be  apparent  that  the  function  of  the  "  aging  "  process  is  to  allow 
the  viscose  to  approach  but  not  quite  reach  that  critical  point  at  which  it  of  itself 
coagulates,  so  that  all  that  is  needed  to  transform  it  into  a  filament  is  to  spin 
it  into  a  weak  neutralizing  bath.  On  account  of  the  fact,  however,  that  it  is 
impossible  to  obtain  absolutely  uniform  cellulose  xanthate,  the  result  is  that 
during  the  "  aging  "  process  certain  portions  of  the  viscose  will  age  too  much, 
and  particles  will  frequently  coagulate  which  greatly  interferes  with  the  spinning 
operations,  by  clodding  the  spinneret  tubes  and  therefore  depreciating  the  quality 
of  the  filaments  rpoduced.  The  object  is  first,  to  produce  a  viscose  which  does 
not  require  to  be  aged  but  nevertheless  will  coagulate  immediately  when  the 
filament  is  brought  into  a  weak  acid  bath,  although  the  viscose  be  fresh,  and  to 
preserve  the  viscose,  and  second,  to  so  check  the  action  of  the  carbon  bisulphide 
as  to  enable  the  viscose  to  be  stored  until  needed  for  spinning. 

Freshly  formed  viscose  ordinarily  would  be  coagulated  by  ejecting  it  through 
a  spinneret  into  a  strong  acid  bath,  but  the  filament  produced  could  not  be  formed 
commercially  as  by  this  process  it  would  be  very  weak  and  possess  little  or  no 
elasticity.  To  produce  a  strong  elastic  thread  the  viscose  must  be  ejected  into 
a  weak  acid  bath;  hence  it  is  necessary  to  employ  a  viscose  solution  which  will 
coagulate  immediately  into  a  filament  when  ejected  into  the  weak  acid  bath. 

t  Acetate  silk  is  made  by  the  Henckel  Donnersmarck  works  at  Stettin. 

J  Chloroform,  ethyl  acetate  and  alcohol,  or  acetic  acid  may  be  employed  as 
solvents  for  cellulose  acetate. 


ARTIFICIAL  SILKS  371 

of  the  cellulose  used,  whereas  with  acetyl  cellulose  the  weight 
of  the  resulting  silk  corresponds  to  about  twice  the  weight  of 
the  cellulose  taken.*  The  silk  made  from  acetyl  cellulose, 
however,  is  less  stable  toward  acids  and  alkalies  than  collodion 
silk,  neither  does  it  dye  as  readily;  and  the  dyeing  is  best  done 
by  adding  the  coloring  matter  to  the  solution  before  spinning. 
The  silk  made  from  acetyl  cellulose  is  known  as  "  cellestron  " 
or  "  acetate  "  silk,  and  is  much  used  for  covering  electric  wires, 
as  it  has  remarkable  insulating  properties. 

The  chief  advantage  of  acetate  silk  over  other  forms  of 
artificial  silk  is  that  it  is  but  little  affected  by  either  hot  or  cold 
water. 

Cellulose  acetate  solutions  may  also  be  employed  for  coating 
cotton  threads  to  produce  an  artificial  horsehair  impervious 
to  water,  f 

The  single  filaments  of  acetate  silk  under  the  microscope 
appear  as  uniform  cylinders  with  occasional  band-like  thicken- 
ings. The  cross-section  is  oval  to  circular,  and  the  average 
diameter  is  42.3  [JL.  The  strength  of  a  thread  of  18  single  fila- 
ments was  found  to  be  226  grams  when  dry  and  128  grams  when 


*  The  production  of  soluble  compounds  of  cellulose  acetate  by  the  action  of 
acetic  anhydride  and  glacial  acetic  acid  on  cotton,  always  requires  the  presence 
of  a  so-called  catalytic  agent.  These  catalytic  agents  as  specified  in  a  large 
number  of  patents  may  be  grouped  in  three  classes:  free  mineral  acids,  weaker 
acids  and  acid  salts,  and  neutral  salts  which  are  readily  dissociated.  Schwalbe 
(Zeit.  an%ew.  Chem.,  1910,  p.  435)  discusses  the  mechanism  of  these  reactions  and 
points  out  that  the  production  of  the  cellulose  acetate  is  always  accompanied 
by  a  more  or  less  profound  modification  of  the  cellulose,  as  evidenced  by  the  cop- 
per reducing  properties  of  the  cellulose  residue  after  the  saponification  of  the  ace- 
tate. Of  the  mineral  acid  group  of  catalytic  agents,  sulphuric  acid  is  by  far  the 
most  important,  and  its  application  is  amply  illustrated  in  the  patents  of  Lederer 
arid  Bayer  &  Co.  The  principal  representatives  of  the  second  group  are  the 
phenolsulphonic  acid  of  Mork's  patent,  and  the  halogenated  fatty  acids  of  Knoll 
&  Co.  Schwalbe  attributes  the  catalytic  effect  of  these  bodies  to  the  presence  of 
limited  quantities  of  free  mineral  acid.  Representatives  of  the  third  group 
include  such  bodies  as  ferrous  sulphate,  ferric  chloride,  diethylamine  sulphate, 
etc.,  found  chiefly  in  Knoll  &  Co.'s  patents.  These  so-called  neutral  salts  possess 
weak  bases  and  free  mineral  acids  are  produced  from  them  by  dissociation. 

t  See  Fr.  Pat.  369,123  of  1906  and  376.578  of  1907. 


372  THE  TEXTILE  FIBRES 

wetted.*  Acetate  silk  is  soluble  in  cold  acetic  acid,  but  insoluble 
in  ammoniacal  copper  hydroxide.  lodin  and  sulphuric  acid 
gives  a  yellow  color,  as  does  also  zinc  chlor-iodide.  It  burns 
quickly  with  a  disagreeable  odor  and  leaves  a  massive  charcoal 
residue.  It  is  distinguished  from  all  other  artificial  silks  by 
its  low  density  (1.25)  and  by  not  swelling  in  water,  f 

9.  Gelatin  Silk. — This  is  a  thread  of  gelatin,  and  conse- 
quently differs  from  the  other  artificial  silks  in  that  it  consists 
of  animal  tissue  and  not  vegetable.  Due  to  this  circumstance, 
it  has  more  analogy  chemically  to  true  silk  than  the  various 
cellulose  silks.  The  manufacture  of  this  fibre  known  as  van- 
duara  silkj  is  conducted  by  forcing  an  aqueous  solution  of  gelatin 
through  a  fine  capillary  tube;  the  thread  so  produced  is  carried 
on  an  endless  band  through  a  drying-chamber.  The  soft 
gelatin  thread,  of  course,  flattens  out  considerably  during  this 
operation,  hence  the  silk  eventually  forms  a  flat,  ribbon-like 
fibre.  After  drying  and  properly  reeling  the  fibre  is  treated 
with  vapor  of  formaldehyde,  which  causes  the  gelatin  to  become 
insoluble  in  water.  By  varying  the  pressure  on  the  gelatin 
solution,  whereby  it  is  forced  through  the  capillary  tube,  the 
thickness  of  the  fibre  may  be  increased  or  diminished.  .  The 
same  result  may  be  attained  by  varying  the  speed  of  the  endless 

*  Compared  with  natural  silk  its  strength  is  as  follows: 


Strength  in  Kilos  per  Square  Millimeter. 

Dry. 

Wet. 

Natural  silk 

37-0 
10.22 
12.  O 
IQ.  I 

37-o 
5-8 

2.  2 
3-2 

Acetate  silk        .    .             

Chardonnet  silk 

Cuprate  silk  

f  Herzog,  Ghent.  ZeiL,  1910,  p.  347. 

|  Vanduara  silk  is  an  English  invention,  the  patentee  being  Adam  Millar. 
(Eng.  Pat.  15,522  of  1894).  The  silk  has  never  appeared  on  the  market  as  a 
commercial  commodity,  and  the  process  does  not  seem  to  have  met  with  any 
marked  degree  of  success.  Another  process  giving  a  thread  of  a  similar  character 
was  that  of  Todtenhaupt  (Eng.  Pat,  25,296  of  1904).  The  latter  uses  an  alka- 
line solution  of  casein. 


ARTIFICIAL  SILKS  373 

band  which  carries  the  thread  after  coming  from  the  capillary 
tube.  The  silk  may  be  dyed  either  in  the  ordinary  way  in 
skein  form  after  reeling,  or  the  gelatin  solution  may  be  colored 
before  the  thread  is  drawn  out.  The  fibre  is  very  lustrous, 
and  if  the  filaments  are  drawn  fine  enough  the  silk  is  soft  and 
pliable. 

10.  Other  Uses  of  Cellulose  Solutions. — It  has  already  been 
mentioned  that  artificial  horsehair  has  been  prepared  in  a  manner 
similar  to  artificial  silk  by  spinning  coarse  filaments  (300*400 
denier)  of  •  the  cellulose  solutions.  Threads  of  silk,  cotton, 
and  linen  are  also  coated  with  a  layer  of  collodion  or  other  cel- 
lulose solution  to  form  lustrous  silk-like  yarns.*  Silk  fish-lines 
coated  in  this  manner  with  pyroxylin  and  dyed  a  light  green 
gives  a  thread  which  is  impermeable  to  water,  has  a  tendency 
to  float,  and  is  practically  invisible  beneath  water. 

Artificial  lace  and  maline  fabrics  have  been  prepared  by 
introducing  a  cellulose  solution  on  an  engraved  metal  cylinder.! 
A  doctor-blade  removes  excess  of  solution  from  the  surface  of 
the  cylinder,  leaving  only  the  engraved  portions  filled  with  the 
liquid.  By  the  rotation  of  the  cylinder  the  cellulose  solution 
is  brought  into  contact  with  a  coagulating  medium,  and  the 
solid  fabric-like  web  is  then  removed  continuously  from  the 
cylinder.  This  artificial  lace,  as  well  as  the  so-called  artificial 
horsehair  is  extensively  employed  in  the  manufacture  of  passemen- 
terie articles,  hat  trimmings,  etc.  Crinol  is  the  name  given 
to  an  artificial  hair  prepared  from  cuprammonium  cellulose; 
meteor  is  a  name  for  a  similar  article. 

\  }  ii.  Properties  of  Artificial  Silk. — The  chief  drawback  to 
the  commercial  success  of  artificial  silk  has  been  its  behavior 
with  water.  When  wetted  with  water  the  fibre  swells  up  to  a 
considerable  extent,  pyroxylin  silk  increasing  in  thickness  by 

*  A  close  imitation  to  natural  black  "horsehair  is  prepared  by  coating  a  5ors 
six-cord  black  thread  with  a  suitable  pyroxylin  solution.  The  coated  thread, 
while  still  black,  has  a  peculiar  superficial  transparency  which  is  so  noticeable 
in  the  natural  hair. 

t  Ratignier  and  Pervilhac,  Eng.  Pat.  13,518  of  1907.  Also  see  Fr.  Pat.  410,721 
of  1909. 


374  THE  TEXTILE   FIBRES 

over  60  per  cent  in  an  hour  and  viscose  silk  by  about  45  per 
cent  in  ten  minutes.  Fibres  of  ordinary  silk  and  also  tussah 
silk  remain  practically  unaltered  when  wetted.  When  wetted 
the  fibre  loses  its  original  strength  *  to  such  a  degree  that  it 
must  be  handled  with  great  care.  Soap  solutions  and  dilute 
acids  have  no  injurious  effect,  but  alkaline  solutions  rapidly 
disintegrate  the  fibre  and  finally  dissolve  it  completely.  The 
material  is  difficult  to  dye,  on  account  of  the  weakening  action 
of  water,  and  the  operation  must  be  carried  out  with  great  care. 
The  dyeing  is  accomplished  without  the  addition  of  either  soap 
or  acid  to  the  bath.  The  basic  coloring  matters  and  some  of 
the  direct  cotton  colors  appear  to  be  the  best  dyestuffs  to 
employ. 

Another  feature  in  which  artificial  silk  is  inferior  to  natural 
silk  is  its  lack  of  "  covering  power."  That  is  to  say,  the  filaments 
of  true  silk  form  a  more  open  thread  which  presents  a  thicker 
appearance  than  a  thread  of  artificial  silk  of  the  same  weight. 
Consequently  a  fabric  woven  from  real  silk  is  more  solid  in 
appearance,  or  better  covered  than  a  corresponding  fabric 
made  of  artificial  silk  threads  of  the  same  size  and  weight. 

Most  of  the  artificial  silk  produced  at  the  present  time  is 
spun  in  about  150  denier  size,  corresponding  to  about  37's 
cotton  yarn.  Silk  of  120  denier  size  is  also  used.  The  number 
of  individual  filaments  in  a  thread  of  120  denier  ranges  from 
1 6  to  25,  hence  the  size  of  the  individual  denier  is  about  5-8 
denier,  in  comparison  with  real  silk  which  averages  2.25  denier 
to  each  filament.  Thiele's  silk  (cellulo)  has  been  made  as 
fine  as  30-50  denier  and  containing  45-60  filaments,  making 
each  of  the  latter  0.5-1.2  denier  in  size,  or  much  finer  than  the 
filament  of  natural  silk.  The  finer  the  denier,  the  greater 
covering  power  of  the  silk,  but  also  the  higher  its  cost.  There 
is  very  little  demand  at '  the  present  time  for  artificial  silk 
finer  than  120  denier. 

*  Strehlenert  has  endeavored  to  prevent  the  loss  of  strength  in  collodion  silk 
when  wetted  by  the  addition  of  formaldehyde  to  the  collodion  solution  (Eng. 
Pat.  22,540  of  1896).  This  process,  however,  does  not  appear  to  have  been  a 
success. 


ARTIFICIAL   SILKS  375 

In  their  dyeing  properties  the  artificial  silks  are  in  general 
similar  to  cotton  or  other  cellulose  fibres.  Owing  to  the  fact 
that  artificial  silk  loses  about  60  per  cent  of  its  strength  when 
wetted  great  care  must  be  used  in  handling  the  yarn  when  dyeing, 
washing  or  bleaching.  According  to  Jentsch  *  collodion  silk 
differs  from  viscose  and  cuprate  silks  in  taking  up  basic  dyes 
directly  without  the  aid  of  a  mordant;  this  is  probably  explained 
by  the  fact  that  collodion  silk  contains  oxycellulose.  The  sub- 
stantive dyes,  however,  are  principally  used  in  the  d)  eing  of 
artificial  silk,  a  topping  with  basic  dyes  often  being  given  in 
order  to  brighten  the  color.  In  dyeing  artificial  silk  the  tempera- 
ture of  the  bath  should  not  exceed  160°  F.  The  principal  defect 
in  the  dyeing  of  artificial  silks  is  tendency  toward  uneven 
colors.  This  defect  is  doubtless  inherent  in  the  structure  of 
the  silk  itself,  the  density  of  the  fibre  lacking  complete  homoge- 
neity. In  collodion  silk  this  defect  has  been  attributed  to 
differences  in  the  amount  of  residual  nitrogen  in  the  fibre,  f 
the  darker  shades  resulting  from  higher  percentages  of  nitro- 
gen. Unevenness  in  colors  may  often  be  remedied  by  topping 
slightly  with  a  basic  dyestuff. 

The  bleaching  of  artificial  silks  should  be  carried  out  rapidly, 
and  the  best  results  are  obtained  by  giving  alternate  baths  of 
sodium  hypochlorite  and  hydrochloric  acid.  The  permanganate 
method  of  bleaching  cannot  be  used  as  it  weakens  the  fibre. 

The  drying  of  artificial  silk  after  dyeing  or  bleaching  should 
be  carefully  conducted ;  overheating  (not  over  110°  F.)  should 
be  avoided,  and  the  silk  should  be  removed  from  the  drying 
chamber  as  soon  as  it  is  properly  dried. 

The  addition  of  Turkey-red  oil  (or  monopol  oil)  is  frequently 
made  to  the  dyebath  for  promoting  the  even  distribution  of 
the  color  and  also  for  producing  a  soft  feel  on  the  silk.  For 
producing  a  "  scroop  "  on  the  fibre  the  silk  is  first  passed  through 
a  soap  bath,  and  then  through  a  bath  containing  a  small  quan- 
tity of  acetic  or  tartaric  acid,  and  dried  without  further  washing. 

In  tensile  strength  artificial  silk  shows  about  one-half  the 
breaking  strain  of  natural  silk;  its  elasticity  is  also  about  one- 

*  Farber-Zeit.,  1908,  p.  36.  f  Clement,  Farber-Zeit.,  1909,  p.  i. 


376 


THE  TEXTILE   FIBRES 


third  to  one-half  that  of  the  latter,  as  shown  in  the  following 
table:  * 


Silk. 

Breaking  Strain  per 
Denier  in  Grams. 

Elasticity, 
Per  Cent. 

Natural  silk   

2    < 

21    6 

Chardonnet 

O   O3 

8  o 

Lehner  

I    43 

7    ^ 

Cuprammonium    ... 

i  6d 

12     < 

Gelatin 

o  6^ 

-i    8 

Viscose  

I    4. 

6  -° 
9r 

When  wetted  the  filaments  of  artificial  silk  show  a  loss  of 
50-70  per  cent  in  tensile  strength. 

The  lustre  of  artificial  silk  is  one  of  its  chief  characteristics. 
In  this  respect  it  is  generally  superior  to  natural  silk.  Its 
lustre,  however,  is  somewhat  metallic  by  reason  of  double 
refraction,  and  this  is  especially  noticeable  in  the  case  of  col- 
lodion silks.  Owing  to  this  property  of  double  refraction 
many  dyestuffs  fluoresce  to  such  an  extent  as  to  be  objectionable. 

Artificial  silk  is  more  hygroscopic  than  cotton;  in  fact  it 
is  about  equal  to  natural  silk  in  this  respect.  The  result  of  a 
large  number  of  tests  at  the  Elberfeld  conditioning  laboratory 
shows  the  hygroscopic  moisture  in  artificial  silks  to  vary  between 
9.30  and  12.99  per  cent,  with  an  average  of  11.3  per  cent.  The 
valuation  of  artificial  silks  is  now  made  on  a  basis  of  1 1  per  cent 
of  moisture,  the  same  as  natural  silk. 

The  density  (specific  gravity)  of  cellulose  artificial  silks 
is  about  1.56  or  about  10-13,  Per  cent  higher  than  for  natural 
silk. 

The  covering  power  of  artificial  silk  is  only  about  one-half 
that  of  natural  silk,  this  being  chiefly  due  to  the  relatively 
larger  size  of  the  individual  filaments,  f 

*  Dreaper  reports  a  sample  of  cellulo  artificial  silk  of  25  denier  and  composed 
of  60  filaments  as  having  a  breaking  strain  of  2.3  grams  per  denier.  This  is 
practically  equivalent  to  natural  silk  in  strength. 

f  Dreaper  (Jour.  Soc.  Dyers  Col.,  1907,  p.  7)  enumerates  the  defects  of  artificial 
silk  as  compared  with  natural  silk,  as  follows:  (i)  The  size,  or  denier,  of  threads 
is  too  great;  (2)  the  individual  filaments  are  much  larger  than  those  of  real  silk; 
(3)  the  strength  and  especially  the  elasticity  are  not  satisfactory;  (4)  the  loss 


ARTIFICIAL  SILKS  377 

12.  Comparison  of  Artificial  Silks. — Hassac  *  gives  a  com- 
parison of  several  makes  or  artificial  silk.  Chardonnet's  and 
Lehners  silks  are  very  similar  in  appearance;  they  are  more 
lustrous  than  real  silk,  but  are  stiffer,  and  do  not  possess  the 
characteristic  feel.  Cellulose  silk  made  by  the  ammoniacal 
copper  oxide  process  is  similar  to  the  former  in  appearance,  but 
its  lustre  is  even  better,  and  it  has  the  characteristic  feel  of  true 
silk.  Lehner's  silk  under  the  microscope  is  characterized  by 
deep  longitudinal  grooves,  and  small  air-bubbles;  its  cross-sec- 
tion is  highly  irregular.  Cuprate  silk  shows  fine  longitudinal 
grooves  and  minute  transverse  lines  in  the  centre  of  the  fibres; 
its  cross-section  is  regular,  approaching  a  circle  or  ellipse.  Ham- 
mers gelatin  silk  is  almost  circular  in  outline,  and  is  free  from 
grooves  and  bubbles;  in  polarized  light  it  is  singly  refracting, 
while  the  others  are  doubly  so.  When  viewed  in  polarized  light 
under  the  microscope  collodion  silk  shows  a  bright  blue  color, 
whereas  viscose  and  cuprammonium  silks  show  a  uniform  bluish 
gray  color. 

There  seems  to  be  considerable  difference  in  the  amount 
of  ash  in  the  artificial  silks  of  different  origin.  Mitchell  and 
Prideaux  give  the  following  figures: 

Per  Cent. 

Collodion  silk 2 . 23 

Viscose  silk 0.28 

Cuprammonium  silk o.  18 

As  the  collodion  silks  always  contain  some  nitrated  com- 
pound,! they  give  a  blue  color  with  diphenylamine  and  sul- 
phuric acid.  The  test  is  carried  out  by  dissolving  a  small  por- 
tion of  the  silk  sample  in  concentrated  sulphuric  acid  to  which 
has  been  added  a  trace  of  diphenylamine.  Collodion  silks 
will  give  a  bright  blue  color  immediately,  whereas  the  other 
cellulose  silks  furnish  only  a  slight  yellow  coloration.  In  place 
of  diphenylamine,  brucine  hydrochloride  may  be  used  in  the 

of  strength  on  wetting  is  excessive;  (5)  the  lack  of  covering  power  reduces  the 
value  of  the  products. 

*Chem.  Zeit.,  1900,  pp.  235,  267,  297. 

f  Collodion  silks  will  usually  show  less  than  0.2  per  cent  of  nitrogen;  ordinary 
silk  contains  about  17  per  cent.  This  trace  of  nitrogen  compound  is  sufficient 
to  distinguish  collodion  silk  from  viscose  and  cuprammonium  silks. 


378  THE  TEXTILE  FIBRES 

•same  manner,  in  which  case  the  color  with  collodion  silk  is  a 
bright  red.  The  other  cellulose  silks  give  a  yellow  color.  Water 
causes  all  the  artificial  silks  to  swell,  while  alcohol  or  glycerol 
contracts  them.  In  strong  sulphuric  acid  the  collodion  silks 
swell  rapidly  and  dissolve;  cuprate  silk  gradually  becomes 
thinner  and  dissolves;  gelatin  silk  only  dissolves  on  strong 
heating.  Chromic  acid  dissolves  all  artificial  silks  in  the  cold; 
real  silk  dissolves  but  slowly,  while  cotton  and  other  vegetable 
fibres  are  unaffected.  Caustic  potash  does  not  dissolve  the 
collodion  or  cellulose  silks,  but  both  the  gelatin  silk  and  real 
silk  are  soluble  on  boiling.  Schweitzer's  reagent  dissolves 
collodion  and  other  cellulose  silks ;  whereas  gelatin  silk  is  insoluble 
but  stains  the  liquid  a  bright  violet.  Alkaline  copper-glycerol 
solution  at  80°  C.  dissolves  real  silk  immediately.  Tussah  and 
gelatin  silks  dissolve  when  boiled  for  one  minute;  the  other 
silks  are  not  affected.  lodin  solution  colors  artificial  silks  an 
intense  red,  which  changes  to  a  transient  pale  blue  on  washing 
with  water  in  the  case  of  collodion  silks,  though  cellulose  silk 
does  not  show  this  blue  color.  lodin  and  sulphuric  acid  stain 
true  silk  a  yellow  color,  gelatin  silk  brown,  while  the  cellulose 
silks  are  colored  blue. 

Cuprate  silk  is  distinguished  from  collodion  silk  by  its  very 
low  copper  index  (see  p.  301).  The  cellulose  of  which  cuprate 
silk  is  composed  appears  to  be  of  a  higher  degree  of  hydration 
than  that  in  viscose  silk,  as  evidenced  by  the  greater  solidity 
of  this  latter  variety  in  the  moist  condition.  Cuprate  silk 
always  retains  traces  of  copper,  giving  the  fibre  a  milky  or  bluish 
appearance;  when  treated  with  ammonium  sulphide  it  gives 
a  grayish  color.  Cuprate  silk  is  also  somewhat  less  limpid 
and  brilliant  than  viscose  silk. 

Massot  gives  the  average  thickness  of  the  filaments  of  dif- 
ferent varieties  of  artificial  silk  as  follows: 

Chardonnet  silk 28 . 8  ^ 

Lehner  silk 35  . 4  [i 

Glanzstoff  silk -. 31 .4  ^ 

Viscose  silk 30 . 5  [x 

Genuine  silk 15  .o  IA 


ARTIFICIAL:  SILKS 


379 


COMPARISON  OF  DIFFERENT  ARTIFICIAL  SILKS  WITH  REAL  SILK  (HASSAC) 


Silk. 

Moisture. 

Sp.Gr. 

Fibres  to 
Sq.  M-n. 

Tens.  Strength, 
Kilo,  per 
Sq.  Mm. 

Elas- 
ticity, 
Per  Ct. 

Air- 
dry, 
Per  Ct. 

Satu- 
rated, 
Per  Ct. 

Wet. 

Dry. 

Wet. 

Dry. 

Real  silk  

8.7i 
II  .  II 
11.32 

10.45 
g.  20 
13.98 

2O.  II 

27.46 
28.94 
26.45 
23.08 
45-56 

.36 
•52 
•53 
•51 
•50 
•37 

9710 
640 
683 

413 
742 
265 

9710 

H35 
1620 
1180 
1550 
945 

37-0 
2.  2 
I  .O 

i-5 

3-2 

o.o 

37-0 
12.  O 
22-3 
16.9 
I9.I 

6.6 

21.6 
8.0 
7-9 
7-5 
12.5 
3-8 

Chardonnet 

(Walston) 
Lehner    

Pauly        

Gelatin 

Silbermann  gives  the  following  more  recent  figures  for  the 
elasticity  of  different  silks: 

Per  Cent. 

Real  silk 17.2 

Tussah  silk 18  .o 

Chardonnet  silk 1 1 . 6 

Vivier  silk 9.6 

It  is  claimed  that  the  elasticity  of  the  Thiele  silk  is  practically 
equal  to  that  of  real  silk. 

According  to  Silvern  the  amount  of  moisture  in  air-dry 
silks  is  as  follows: 

Per  Cent. 

China  raw  silk 7-97 

Tussah  silk . . 8. 26 

Chardonnet  silk 10.37-11.17 

Lehner  silk 10.71 

Glanzstoff  (cuprammonium) 10.04 

Viscose  silk 1 1 . 44 

Gelatin  silk 13 . 02 

Strehlenert  and  Westergren  give  the  following  figures  for 
the  tensile  strengths  of  various  natural  and  artificial  silks :  * 

*  Cross. and  Bevan  (Jour,  Soc.  Chem.  Ind.,  1908,  p.  1189)  give  the  following 
data  regarding  the  strength  of  artificial  silks: 


Artificial  Silks. 

True  Silk  Boiled-off. 

Breaking  strain  per  unit  denier  (grams)  .  . 
Stretch  under  breaking  strain  (per  cent)  . 
True  elasticity  (per  cent)  

I  .0-1  .4 

13-17 
4-c 

2.0-2.5 

15-25 
4-5 

380 


THE  TEXTILE  FIBRES 


The  figures  indicate  the  breaking  strains  in  kilograms  per  square 
millimetre  section: 

NATURAL  SILKS 


Dry. 


Wet. 


Chinese  silk 53 . 2 

French  raw  silk 50 . 4 

French  silk,  boiled  off 25.5 

dyed  red  and  weighted 20 .  o 

blue-black,  weighted  110% 12.1 

black,  weighted  140% 7.9 

black,  weighted  500% 2.2 

ARTIFICIAL  SILKS 

Dry. 

Chardonnet's  collodion,  undyed 14.7 

Lehner's  collodion,  undyed 17.1 

Strehlenert's  collodion,  undyed 15.9 

Cuprate  (Glanzstoff),  undyed 19 .  i 

Viscose  silk,  early  samples 11.4 

latest  samples 21.5 

Cotton  yarn  (for  comparison) 11.5 


46.7 

40.9 

13-6 

15-6 

8.0 

6-3 


Wet. 


1-7 
4-3 
3-6 
3-2 
3-5 

18.6 


The  commercial  sizes  in  which  artificial  silk  is  generally 
employed  is  from  no  to  150  denier  for  weaving  and  braiding; 
coarser  numbers  are  used  for  passementerie  articles,  etc.  By 
the  Thiele  process  of  manufacture  artificial  silk  threads  of  40 
denier  and  even  less  may  be  produced,  each  thread  consisting 
of  80  filaments.  In  this  variety  of  silk  the  single  silk  filament 
is  about  as  fine  as  that  of  natural  silk  (2  to  3  denier),  and  this 
gives  the  thread  greater  elasticity  and  softness.  In  other 
varieties  of  artificial  silk  the  size  of  the  individual  filaments 
averages  5  to  8  denier,  or  about  twice  that  of  the  natural 
silk  fibre.  Owing  to  its  structure  it  is  also  claimed  that  Thiele's 
silk  has  much  greater  strength  than  other  varieties  of  artificial 
silk;  its  strength,  in  fact,  being  only  20  per  cent  less  than  that 
of  real  silk.  Its  loss  in  strength  on  wetting  is  also  relatively 
small. 


ARTIFICIAL  SILKS  381 

13.  Animalized  Cotton. — Cotton  may  be  "  animalized  " 
that  is,  given  the  dyeing  properties  possessed  by  animal  fibres — 
in  a  variety  of  ways.  The  material  may  be  impregnated  with 
albumin  and  afterward  steamed;  this  method  is  employed  to 
some  extent  in  printing,  being  used  chiefly  in  connection  with 
the  direct  cotton  colors  to  prevent  their  bleeding.  A  solution 
of  casein  may  also  be  used  instead  of  albumin,  with  similar 
results.  The  same  property  may  also  be  imparted  to  cotton 
by  treatment  with  tannic  acid  and  gelatin  or  lanuginic  acid 
(solution  of  wool  in  caustic  alkali),  but  with  doubtful  results; 
though  Knecht  describes  a  method  which  is  said  to  give  satisfac- 
tion, the  cotton  being  impregnated  with  a  solution  of  lanuginic 
acid  and  allowed  to  dry  in  the  presence  of  formaldehyde,  when 
the  fibre  becomes  coated  with  an  insoluble  film  possessing  a 
remarkable  affinity  for  the  substantive  dyes.  Vignon  claims 
that  by  treating  cotton  under  pressure  with  ammonia  in  pres- 
ence of  zinc  chloride  or  calcium  chloride,  the  fibre  acquires 
an  increased  affinity  for  the  basic  and  acid  dyestuffs.  His 
results,  however,  have  not  been  confirmed. 

A  silk-like  appearance  may  also  be  given  to  vegetable  fibres 
by  treatment  with  a  solution  of  silk  (fibroin)  in  some  suitable 
solvent,  such  as  hydrochloric,  phosphoric,  or  sulphuric  acid, 
or  cuprammonium,  etc.  The  silk  employed  is  made  up  of 
scraps  and  waste  which  would  otherwise  be  useless.  Better 
r^plts  are  obtained  if  the  cotton  material  be  treated  with  a 
metric  or  .tannic  acid  mordant  before  immersion  in  the  silk 
solution.  It  should  afterward  be  calendered  and  polished  in 
order  to  obtain  a  glossy  appearance. 


CHAPTER  XVI 
LINEN 

i.  Preparation. — Linen  is  the  fibre  obtained  from  the  flax 
plant,  botanically  known  as  Linum  usitatissimum*  The  fibre 
is  prepared  from  the  bast  of  the  plant  by  a  process  called  retting. 
which  has  for  its  purpose  the  separation  of  the  fibrous  cellulose 
from  the  woody  tissue  and  other  plant  membranes.  Historically 
linen  appears  to  have  been  the  earliest  vegetable  fibre  employed 
industrially,!  having  been  used  at  a  much  earlier  date  than 
cotton.  Though  grown  more  or  less  in  every  country, {  at  present 
the  cultivation  of  flax  is  principally  carried  on  in  France,  Ireland, 

*  Botanists  recognize  upward  of  one  hundred  species  of  the  flax  plant,  but, 
of  all  these,  the  only  one  possessing  industrial  importance  and  the  only  one 
readily  cultivated  is  the  Linum  usitatissimum,  which  has  a  blue  flower.  The 
North  American  Indians  have  long  used  the  fibre  of  L.  lewisii,  which  differs 
from  the  ordinary  cultivated  flax  in  having  three  stems  growing  from  a  perennial 
root.  The  most  ancient  species  of  flax  brought  under  cultivation  is  thought  to 
be  L.  angustifolium;  the  Swiss  lake-dwellers  are  said  to  have  grown  it,  as  also  the 
ancient  inhabitants  of  northern  Italy.  The  flax  cultivated  in  the  eastern  coun- 
tries, in  Assyria  and  Egypt,  appears  to  have  been  the  common  variety  L.  usilatmi- 
mum.  Greek  or  spring  flax,  L.  crepitans,  is  a  small  plant  somewhat  cult^ated 
in  Russia  and  Austria.  Two  other  varieties  are  also  cultivated  to  some  extent 
in  Austria,  perennial  flax  (L.  perenne)  and  purging  flax  (L.  catharticu m) .  The 
flax  employed  by  the  North  American  Indians  for  making  fish  nets  was  also  a 
perennial  plant,  L.  lewisii. 

f  Egyptian  linen  fabrics  (mummy-cloths)  have  been  found  which  are  probably 
over  4500  years  old.  Flax  is  mentioned  in  the  book  of  Exodus  as  one  of  the 
products  of  Egypt  in  the  time  of  the  Pharoahs.  Solomon  purchased  linen  yarn 
in  Egypt  and  Herodotus  speaks  of  the  great  flax  trade  of  Egypt.  Numerous 
pictorial  representations  of  the  cultivation  and  preparation  of  flax  are  sculptured 
on  the  walls  and  tombs  of  Thebes,  showing  the  varieties  of  flax  in  the  red  and  white 
flower,  the  manner  of  pulling,  retting,  etc.,  as  practised  when  Jacob  dwelt  in 
the  land  of  Goshen. 

JThe  world's  annual  production  of  linen  is  about  1,000,000,000  pounds. 

382 


LINEN  383 

Belgium,  Holland,  Russia,  United  States,*  and  Canada.f  The 
bast  tissue,  which  is  used  for  the  fibre,  is  situated  between  the 
bark  and  the  underlying  woody  tissue  (see  Fig.  80). 

The  flax  plant  is  annual  in  growth  and  rather  delicate  in 
structure.  It  grows  to  about  40  inches  in  height;  the  stem 
is  slender,  branching  only  slightly  at  the  top,  and  bears  naked, 
lanceolate,  alternate  leaves.  The  flower  is  mostly  sky-blue, 
though  sometimes  white;  the  seed-capsules  are  five-lobed  and 
globular,  and  of  the  size  of  peas.f 


*  Only  in  the  vicinity  of  Yale,  Michigan,  at  Northfield  and  Heron  Lake,  Minne- 
sota, and  at  Salem  and  Scio,  Oregon,  is  flax  cultivated  in  America  for  the  production 
of  spinning  fibre.  In  all  these  localities  the  seed  is  saved,  and  it  is  doubtful  if  the 
industry  would  yield  sufficient  profits  from  the  production  of  the  fibre  alone  to 
warrant  its  continuance  under  present  conditions.  (Yearbook,  Dept.  Agric., 

1903-) 

t  The  Department  of  Agriculture  gives  the  following  marks  of  the  commercial 
grades  of  flax  imported  into  the  United  States. 

From  Russia:  Russian  flax  is  known  either  as  Slanetz  (dew-retted)  or  Mot- 
chenetz  (water-retted);  ungraded  fibre  is  called  Siretz.  The  latter  comes  chiefly 
from  St.  Petersburg,  and  is  known  under  the  names  of  Bejedsk,  Krasnoholm, 
Troer,  Kashin,  Gospodsky,  Nerechta,  Wologda,  Jaraslav,  Graesowetz,  and  Kos- 
roma;  all  these  varieties  are  slanetz.  Pochochon,  Ouglitz,  Rjeff,  Jaropol,  and 
Stepurin  are  motchenetz.  From  Archangel  are  brought  slanetz  varieties  known 
as  First  Crown,  Second  Crown,  Third  Crown,  Fourth  Crown,  First  Zabrack  and 
Second  Zabrack.  From  Riga  are  obtained  motchenetz  varieties  graded  from  the 
standard  mark  K  through  HK,  PK,  HPK,  SPK,  HSPK,  ZK,  GZK,  and  HZK. 

From  Holland:    Dutch  flax  is  graded  by  the  marks  — ,  — ,  VI,  VII,  VIII,  IX. 
From  Belgium:    Flemish  flax  (or  blue  flax)  includes  Bruges,  Thisselt,  Ghent, 
Lokeren,  and  St.  Nicholas,  and  is  graded  as  — ,  -,  — ,  VI,  VII,  VIII,  IX.     Cour- 

I      II     I     II    II    I 
trai  flax  is  graded  as  -,  -,  -,  -,  -,  -,  VI. 

Fumes  and  Bergues.  flax  is  graded  A,  B,  C,  D.  Walloon  flax  is  graded  II, 
III,  IV.  Zealand  flax  is  graded  IX,  VIII,  VII,  VI.  Friesland  flax  is  graded  D,  E, 
Ex,  F,  Fx,  Fxx,  G,  Gx,  Gxx,  Gxxx. 

From  France:  French  flax  is  known  by  the  districts  of  Wavrin,  Flines,  Douai, 
Hazebrouck,  Picardy,  and  Harn^s. 

From  Ireland:  Irish  flax  comes  as  scutched  and  mill  scutched,  and  is  known 
by  the  names  of  the  counties  in  which  it  is  raised. 

From  Canada:  This  flax  has  no  standard  of  marks  or  qualities. 

J  Generally,  about  two  bushels  of  flax-seed  are  sown  per  acre,  and  the  yield 
in  finished  fibre  is  from  600  to  800  pounds,  having  a  market  price  of  about  12 


384 


THE  TEXTILE  FIBRES 


Besides  being  cultivated  for  its  fibre,  the  flax  plant  is  also 
grown  for  its  seed,  which  yields  the  valuable  oil  known  as  linseed. 
It  possesses  good  drying  qualities,  and  hence  is  extensively 

used  for  the  preparation  of 
paints  and  varnishes.  The  best 
seed-flax  is  grown  in  tropical  and 
subtropical  countries,  whereas 
the  best  fibre-flax  is  grown  in 
more  northern  climates.  The 
seed  obtained  from  the  latter 
variety,  though  utilized  as  a 

cents  per  pound.  The  yield  of  seed  is 
from  8  to  10  bushels  of  52  pounds  each. 
The  growing  of  a  flax  crop  is  very  ex- 
hausting to  the  soil;  potash  and  phos- 
phoric acid  are  the  chief  ingredients  that 
the  soil  requires  to  produce  a  good  crop  of 
flax  for  either  fibre  or  seed.  It  requires 
from  400  to  600  pounds  of  mineral  or  phos- 
phate fertilizers  per  acre,  besides  barn- 
yard and  other  manures,  to  keep  the  soil 
in  condition,  and  then  only  two  to  three 
crops  can  be  raised  in  succession. 

New  England  formerly  cultivated  flax 
on  the  extensive  scale  for  the  fibre,  but 
this  was  rapidly  replaced  by  the  introduc- 
tion of  cotton  manufacturing,  which  to- 
gether with  the  exhaustion  of  the  soil,  led 
to  the  abandonment  of  this  industry  in 
that  part  of  the  United  States  early  in 
the  nineteenth  century.  There  are  large 
quantities  of  flax  grown  in  America, 
chiefly  in  the  Northwestern  States;  but 
it  is  grown  almost  entirely  for  seed,  the 
plant  being  allowed  to  ripen  fully  before 
harvesting,  and  the  flax  straw  being  burned  to  get  rid  of  it.  The  United  States, 
in  fact,  furnishes  about  one-fourth  of  the  world's  supply  of  linseed  oil.  In  1900- 
1901,  the  yield  of  oil  was  about  40,000,000  gallons.  The  Argentine  Republic  is 
the  greatest  flax-growing  country  in  the  world;  but  the  plant,  in  this  case  too, 
is  grown  only  for  the  seed  and  the  straw  is  burned.  The  yield  of  oil  from  this 
country  is  about  55,000,000  gallons,  or  about  one-third  of  the  world's  supply. 
Russia  has  a  large  acreage  devoted  to  the  cultivation  of  flax;  the  fibre,  however, 
is  of  minor  importance,  being  woody  and  subject  to  great  waste  in  preparation. 
In  India  flax  is  also  mainly  grown  for  the  seed. 


FIG.  80.— The  Ancient  Flax  Plant 

(Linum  angustifolium) . 
(After  Bulletin  U.  S.  Dept.  Agric.) 


LINEN  385 

by-product,  produces  only  an  inferior  grade  of  oil.  The  oil-cake 
left  after  expressing  the  oil  from  the  seed  is  an  excellent  cattle- 
food  and  is  largely  used  for  this  purpose. 

The  flax  plant,  after  attaining  its  proper  growth,  is  either  cut 
down  or  pulled  up  by  its  roots,  and  subjected  to  a  process  tech- 
nically known  as  rippling,  the  plants  being  drawn  through  a 
machine  consisting  of  upright  forks  which  remove  the  seeds 
and  leaves.  The  remaining  stalks  are  then  tied  in  bundles 
and  placed  in  stagnant  water,  where  they  are  allowed  to 
remain  for  a  number  of  days.  Active  fermentation  soon 
starts,  resulting  in  the  decomposition  of  the  woody  tissues 
enclosing  the  cellulose  fibres.  When  the  process  has  gone 
sufficiently  far,  the  bundles  of  fermented  stalks  are  removed 
and  passed  through  a  number  of  mechanical  operations,  whereby 
the  decomposed  tissues  are  removed  and  the  linen  fibres  are 
isolated  in  a  purified  condition.  This  method  of  retting  with 
stagnant  water  is  known  as  "  pool-retting."  As  the  fermenta- 
tion causes  the  evolution  of  considerable  gas,  in  order  to  keep 
the  bundles  of  stalks  submerged,  they  are  loaded  with  stones 
or  boards.  The  time  of  steeping  in  the  water  varies  with 
circumstances  from  five  to  ten  days.*  Another  method  of 
retting  is  to  steep  in  running  water.  The  famous  Courtrai 

*  Dodge  gives  the  following  notes  relative  to  the  retting  of  flax:  "  For  dew- 
retting  a  moist  meadow  is  the  proper  place,  the  fibre  being  spread  over  the  ground 
in  straight  rows  at  the  rate  of  a  ton  to  an  acre.  If  laid  about  the  ist  of  October 
and  the  weather  is  good,  a  couple  of  weeks  will  suffice  for  the  proper  separation 
of  the  fibre  and  woody  matter.  For  pool-retting  the  softest  water  gives  the  best 
results,  and  where  a  natural  pool  is  not  available,  such  as  the'bog-holes'  in  Ireland, 
'  steep  pools  '  will  have  to  be  built.  A  pool  30  feet  long,  10  feet  wide,  and  4  feet 
deep  will  suffice  for  an  acre  of  flax.  Spring  water  should  be  avoided,  or,  if  used, 
the  pool  should  be  filled  some  weeks  before  the  flax  is  ready  for  it,  in  order  to 
soften  the  water.  It  should  be  kept  free  from  all  mineral  and  vegetable  impuri- 
ties. The  sheaves  are  packed  loosely  in  the  pool.  .  .  .  Fermentation  is  shown 
by  the  turbidity  of  the  water  and  by  bubbles  of  gas.  ...  If  possible,  the  thick 
scum  which  forms  on  the  surface  should  be  removed  by  allowing  a  slight  stream 
of  water  to  flow  over  the  pool.  The  fibre  sinks  when  decomposition  has  been 
carried  to  the  proper  point,  though  this  is  not  always  a  sure  indication  that  it  is 
just  right  to  take  out.  In  Holland,  the  plan  is  to  take  a  number  of  stalks  of  aver- 
age fineness,  which  are  broken  in  two  places  a  few  inches  apart.  If  the  woody 

ortion  or  core  pulls  out  easily,  leaving  the  fibre  intact, it  is  ready  to  come  out. 

"'ie  operation  usually  requires  from  five  to  ten  days." 


386 


THE  TEXTILE   FIBRES 


flax  of  Belgium  is  retted  in  this  manner  in  the  river  Lys.  The 
flax-straw,  after  pulling,  is  placed  in  crates  and  submerged 
in  the  water  of  this  stream  for  a  period  of  four  to  fifteen  days, 
depending  on  the  temperature  and  other  conditions.  Courtrai 


A     B 


FIG.  81. — Cross-section  of  Flax-straw. — A,  layer  of  cuticular  cells;  B,  interme- 
diate layer  of  cortical  parenchym;  C,  has  fibres  in  groups,  being  the  flax 
fibres  proper  (note  secondary  thickening  of  cell-walls);  D,  cambium  layer; 
E,  woody  tissue.  (Cross  and  Bevan.) 

flax  is  of  a  creamy  color,  whereas  pool-retted  flax  has  a  rather 
dark  bluish  brown  color.  The  excellent  qualities  of  the  Courtrai 
flax  are  said  to  be  due  to  the  action  of  the  soft,  slowly  running, 
almost  sluggish  waters  of  the  river  Lys,  and  to  the  peculiar 


LINEN  387 

ferment  existing  therein.  Another  method  employed  for 
obtaining  the  fibre  from  flax  is  known  as  dew-retting,  as  the 
flax-straw  is  spread  out  in  a  field  and  exposed  for  a  couple  of 
weeks  to  the  action  of  the  dew  and  the  sun.  Dew-retting, 
however,  gives  the  most  uneven  and  least  valuable  product 
of  the  three  methods  employed,  and  the  fibre  is  rather  dark 
in  color.  There  have  also  been  several  chemical  methods 
proposed  for  retting  flax,  such  as  heating  with  water  under 
pressure,  boiling  with  solutions  of  oxalic  acid,  soda  ash,  caustic 
soda,  etc.  None  of  these,  however,  have  proved  of  any  industrial 
value,  and  the  older  natural  methods  are  still  adhered  to.  Addi- 
tions of  various  chemicals  to  the  retting  waters  have  at  times 
proved  of  value,  hydrochloric  or  sulphuric  acid  sometimes 
being  used  to  advantage.* 

The  intercellular  substance  holding  the  flax  fibres  together 
consists  mostly  of  calcium  pectate,  and  the  real  object  of 
retting  is  to  render  this  substance  soluble,  so  that  it  may  be 
removed  by  the  after-processes  of  treatment.  Winogradsky  has 
succeeded  in  isolating  the  particular  organism  f  that  is  the  active 
agent  in  the  pectin  fermentation.  It  is  an  anaerobic  bacillus 
which  readily  ferments  pectin  matters,  but  has  no  action  on 
cellulose. 

Beijerinck  and  van  Delden  ascribe  the  bacterial  action  in 
flax  retting  to  a  fermentation  of  the  pectose  first  into  pectin, 
and  then  into  sugars,  through  the  action  of  an  enzyme,  pectinase, 
secreted  by  the  bacteria.  According  to  Behrens  the  active 
agents  in  dew  retting  are  mould  fungi. 

*  Schenck's  method  of  retting  is  to  steep  in  warm  water,  a  constant  temperature 
of  35°  C.  being  maintained.  It  is  said  that  the  fermentation  may  be  completed 
by  this  method  in  fifty  to  sixty  hours,  and  gives  a  larger  yield  and  a  better  product 
than  the  natural  processes  of  retting.  In  steam-retting,  the  bundles  of  flax- 
straw  are  placed  in  iron  cylinders  and  heated  with  live  steam  or  hot  water  under 
pressure,  but  the  process  does  not  appear  to  be  successful.  Loppens  and 
de  Swarte  (Eng.  Pat.  14,781  of  1895,)  introduced  a  method  in  which  the  flax 
straw  is  placed  upright  in  a  tank  through  which  passes  an  upward  current  of  water. 
The  dissolved  matters  form  a  heavy  solution  which  falls  to  the  bottom. 

f  There  seems  to  be  some  confusion  as  to  the  exact  species  of  this  organism. 
Winogradsky  designates  it  as  the  Bacillus  amylobacter,  while  Beijerinck  and  Van 
Dalden  call  it  Granulobacter  pectinovorutn. 


388  THE  TEXTILE  FIBRES 

The  water-retting  of  flax  is  described  by  Stormer  as  a  biological 
process  induced  by  the  action  of  definite  organisms,  the  chief 
of  which  is  an  anaerobic  Plectridium,  which  in  the  absence  of 
air  ferments  the  pectin  substances  of  the  cellular  material 
uniting  the  parenchymous  tissues,  and  thus  causes  a  loosening 
of  the  bast  fibres.  The  exclusion  of  oxgyen,  which  is  necessary 
that  the  fermentation  may  be  set  up,  is  brought  about  by  nu- 
merous oxygen-consuming  bacteria  and  fungi.  The  products 
formed  by  the  fermentation  of  the  pectin  substances  are  hydro- 
gen and  carbon  dioxide  and  organic  acids,  especially  acetic 
and  butyric  and  small  quantities  of  valeric  and  lactic  acids. 
The  injurious  action  of  the  acids  produced,  especially  butyric 
acid,  may  be  considerably  diminished  by  adding  alkali  or  lime 
to  the  retting  liquid.  It  is  also  advantageous  to  inoculate  the 
liquid  at  the  beginning  of  the  retting  with  pure^cultures  of  the 
anaerobic  Plectridium.*' 

By  adding  salts  promoting  the  growth  of  the  bacillus  to  the 
water  employed  in  retting,  it  has  been  found  possible  to  reduce 
the  time  of  retting  very  considerably. 

The  substances  classified  in  a  general  way  as  "  pectin  mat- 
ters "  form  the  intercellular  matter  between  the  elemental 
cells  of  the  bast  fibres,  and  serve  the  purpose  of  a  cementing 
medium  to  hold  the  small  elements  of  the  fibre  together.  Their 
character  is  that  of  a  resinous  gum.  By  certain  investigators 
this  resinous  matter  has  been  given  the  name  pectose.  It  is 
hardly  likely,  however,  that  this  substance  consists  of  a  single 
chemical  compound,  but  it  is  more  probably  a  mixture  of  several 
chemical  individuals.  By  heating  with  dilute  acid,  pectose 
is  converted  into  a  series  of  products  which  have  received  con- 
siderable attention  from  botanical  chemists;  the  products 
include  pectin,  para-pectin,  meta-pectin,  pectosic  acid,  pectic 
acid,  para-pectic  acid,  meta-pectic  acid,  etc.  Pectin  and  espe- 
cially para-  and  meta-pectin  are  soluble  in  water,  whereas 
pectic  acid  is  not.  Therefore,  if  it  is  desirable  to  separate 
the  elements  of  a  vegetable  tissue,  it  is  necessary  to  stop  the 
action. of  the  retting  agents  before  the  formation  of  pectic  acid. 

*  See  Stormer,  Chent.  Cenlr.,  1905,  p.  41. 


LINEN  389 

In  the  case  of  the  preparation  of  linen,  however,  it  appears  to 
be  necessary  not  to  dissolve  out  all  the  pectose  derivatives  from 
the  fibre,  but  to  allow  of  the  formation  of  some  pectic  acid,  as 
this  makes  the  surface  of  the  fibre  more  brilliant*  and  leaves 
it  stronger  and  more  elastic. 

It  has  been  claimed  that  fatty  acids  exert  a  solvent  action 
on  the  resinous  and  pectin  matters  present  in  vegetable  fibres, 
and  a  method  for  the  decortication  of  flax  and  other  bast  fibres 
has  been  devised  as  follows:  The  raw  fibres  are  impregnated 
with  boiling  soap  solutions,  after  which  ammonium  chloride 
is  added,  which  liberates  the  fatty  acids.  After  several  hours' 
treatment  these  dissolve  all  gummy  and  resinous^  matters ;  the 
fibres  are  then  treated  with  weak  caustic  alkali,  after  which  they 
are  washed  and  dried  when  they  should  be  thoroughly  dis- 
integrated. Good  results  are  said  to  be  obtained  by  this  method. 

The  flax  stalks,  after  being  deprived  of  their  leaves  and  seeds 
by  rippling,  are  known  as  flax-straw.  The  latter  in  the  air- 
dry  condition  contains  from  73  to  80  per  cent  of  wood,  marrow, 
and  bark,  and  20  to  27  per  cent  of  bast.f  The  general  structure 

*  Lecomte,  Textiles  vegetaux. 

f  According  to  Prof.  Hodge  (of  Beltast),  the  proportions  among  the  con- 
stituent parts  of  the  flax  plant  are  as  follows: 

Pounds. 

Dried  flax  plants 77)0 

Bolls 1946 

Seed 910 

Raw  fibre  stalks 5824 

Loss  in  steeping • 1456 

Retted  stalks 4368 

Finished  fibre -. .      702 

Hence,  the  weight  of  the  fibre  was  equal  to  about  9  per  cent  of  the  dried  flax 
stalk  with  the  seed-bolls,  or  to  12  per  cent  of  the  bolted  straw,  or  to  over  16  per 
cent  of  the  retted  straw. 

According  to  Schenck  (American  process),  the  following  proportions  were 
obtained. 

Tons. 

Dried  flax  straw 100 

Bolls 33 

Loss  in  steeping 27.5 

Separated  in  scrutching 32.13 

Finished  fibre , .  .  .         5.9 

Low  and  pluckings 1.47 


390 


THE   TEXTILE  FIBRES 


of  flax-straw,  and  of  bast  stalks  in  general,  is  shown  in  the 
schematic  drawing  (Fig.  83). 

The  linen  fibre  as  it  is  obtained  from  the  plant  and  as  it 
appears  in  trade  is  in  the  form  of  filaments,  the  length  *  of 
which  varies  considerably  with  the  manner  and  care  employed 
in  decorticating,  and  may  be  from  a  few  inches  to  several  feet.f 
These  filaments  are  composed  structurally  of  small  elements 
or  cells,  consisting  of  practically  pure  cellulose.^  They  are 


V, 


FIG.   82. — Flax  Fibres.     (X400.)     a,  a',  cross-sections;    b,  longitudinal  views; 
c,  ends.     (After  Cross  and  Bevan.) 

*  Flax  fibre  is  from  12  to  36  inches  in  length,  silver  gray  when  dew-retted,  yel- 
lowish white  when  water-retted,  capable  of  fine  subdivision,  soft  and  flexible^  and 
is  the  strongest  of  the  fine  commercial  bast  fibres.  It  is  used  for  making  linen  sew- 
ing thread,  shoe  thread,  bookbinders'  thread,  fishing-lines,  seine  twine,  the  better 
grades  of  wrapping  twine,  and  knit  underwear,  and  for  weaving  into  handkerchiefs, 
towelling,  table-linen,  collars  and  cuffs,  shirt-bosoms,  and  dress-goods.  The 
finer  grades  of  linen  damasks  are  imported,  as  the  weaving  of  these  goods  is 
slow  work,  and  requires  a  kind  of  labor  not  commonly  found  in  this  country. 
(Yearbook,  Dept.  Agric.,  1903.) 

f  Good  flax  should  average  20  inches  in  length  and  be  free  from  fibres  less 
than  12  inches  in  length. 

|  Cottonized  flax  was  a  name  given  to  a  product  made  by  disintegrating  flax 
by  chemical  means  into  a  fine  cotton-like  material.  The  flax  was  first  treated  with 
a  dilute  solution  of  caustic  soda,  then  impregnated  with  a  solution  of  soda  ash, 
and  immersed  in  a  dilute  solution  of  sulphuric  acid,  the  fibres  being  disintegrated 
by  the  liberation  of  the  carbon  dioxide  gas.  Fabrics  woven  from  yarns  of  this 
material,  however,  were  found  to  be  deficient  in  strength,  and  the  process  never 
met  with  commercial  success.  It  was  proposed  by  Claussen  in  1851. 


LINEN 


391 


5    3    1 


2    4 


uniformly  thick,  and  average  12  to  25  [L  in  diameter  and  25 
to  30  mm.  in  length.  Their  structure  is  rather  regular,  being 
cylindrical  in  shape,  though  somewhat  polygonal  in  cross- 
section.  A  peculiarity  in  the  appearance  of  the  cells  is  the 
occurrence  of  faintly  marked  "  dislocations  "*  or  so-called 
"  nodes  "  extending  transversely  and  often 
in  the  foim  of  an  "  X."  These  nodes 
may  be  made  more  apparent  by  staining 
with  methyl  violet  or  chlor-iodide  of  zinc 
solution.  The  cell-wall  is  quite  uniform 
in  thickness,  and  the  lumen  or  internal 
canal  is  very  narrow,  and  often  is  but 
faintly  apparent  as  a  dark  line.  The  cross- 
section  of  the  linen  fibre  shows  no  yellow 
circumferential  stain  when  treated  with  sul- 
phuric acid,  though  the  lumen  shows  up 
as  a  yellow  spot.  Wiesner  gives  the  fol- 
lowing dimensions  of  several  varieties  of  flax 
filaments:! 


FIG.  83.  —  Diagram 
of  Flax-straw,  i, 
marrow;  2,  woody 
fibre;  3,  cambium 
layer;  4,  bast  fibre; 
5,  rind  or  bark. 
(After  Witt.) 


Kind  of  Flax. 

Mean  Length 
of  the  Purified 
Flax  Fibre, 
mm. 

Mean  Breadth, 
mm. 

Egyptian 

060 

o  2<?t; 

Westphalian  

75° 

o.  114 

Belgian  Courtrai  
Austrian  

370 
410 

o.  105 

d  202 

Prussian 

280 

o  .no 

*  Hohnel  (Ueber  den  Einfluss  des  Kindendruckes  auf  der  Beschaffenteil 
der  Bastfasern,  Jahrbuch,  Wiss.  Bot.,  vol.  15,  p.  311)  considers  that  these  disloca- 
tions or  cross-folds  are  of  physiological  origin  resulting  from  inequalities  in  the 
radial  pressure  of  the  tissues  in  the  plant.  Schwendener  (Ueber  die  "  Ver- 
schiebungen"  der  Bastfasern.  Ber.  Deutsch.  Bot.  Gesell.,  vol.  12,  p.  239),  on  the  other 
hand,  considers  them  as  resulting  from  artificial  influences  during  the  processes 
of  preparation,  as  fibres  obtained  by  simple  retting  in  water  show  almost  a  com- 
plete absence  of  such  distortions. 

t  Dodge  gives  the  following  dimensions  for  the  elements  of  the  flax  fibre: 
Length,  0.157  to  2.598  inches;  mean,  about  i  inch;  diameter,  0.006  to  0.00148 
inch;  mean,  o.ooi  inch. 


392  THE  TEXTILE   FIBRES 

2.  Chemical  and  Physical  Properties. — The  flax  fibre  appears 
to  consist  of  pure  cellulose  and  shows  no  signs  at  all  of  being 
lignified.* 

In  order  to  isolate  pure  flax  cellulose,  Cross  and  Bevan 
have  recommended  the  following  procedure.  The  non-cellulosic 
constituents  of  flax  are  pectic  compounds  which  are  soluble 
in  boiling  alkaline  solutions.  The  proportion  of  such  con- 
stituents varies  from  14  to  33  per  cent  indifferent  varieties  of 
flax.  They  may  be  completely  extracted  by  first  boiling  the 
fibre  in  a  dilute  solution  of  caustic  soda  (i  to  2  per  cent);  the 
residue  will  consist  of  flax  cellulose,  with  small  remnants  of 
woody  and  cuticular  tissue,  together  with  some  of  the  oils  and 
waxes  associated  with  the  latter.  By  treatment  with  a  weak 
solution  of  chloride  of  lime,  the  woody  tissue  is  decomposed, 
and  is  then  removed  by  again  boiling  in  dilute  alkali.  The 
remaining  cellulose  is  then  further  purified  from  residual  fatty 
and  waxy  matters  by  boiling  with  alcohol  and  finally  with 
ether-alcohol  mixture.  Flax  cellulose  prepared  in  this  manner 
appears  to  be  chemically  indistinguishable  from  cotton  cellulose. 

Linen  becomes  strongly  swollen  by  treatment  with  Schweit- 
zer's reagent  (see  Fig.  84),  but,  unlike  cotton,  f  it  does  not 
completely  dissolve  therein. 

In  swelling  the  fibre  blisters  considerably,  but  not  in  as 
regular  a  manner  as  cotton.  The  inner  layers  of  the  cell  with- 

*  Though  the  flax  fibre  is  generally  considered  as  non-lignified,  Hohnel  (Zur 
Mikroskopie  der  Hanf  und  Flachsfaser,  Zeitschr.  Nahr.  Unters.  Hyg.  Warenk., 
1892,  p.  30)  is  of  the  opinion  that  very  short  sections  with  lignified  cross- walls 
occur  between  long  sections  with  walls  of  pure  cellulose.  Herzog  determined 
the  lignin  in  fibres  from  different  parts  of  the  plant  by  the  methyl  oxide  method, 
and  found  that  fibres  from  the  root  contained  3.8  per  cent,  from  the  middle  of 
the  stem  2.36  per  cent  and  from  the  tip  of  the  stem  1.64  per  cent  of  lignin.  By 
bleaching  the  lignin  is  entirely  removed. 

t  According  to  Hanausek  (Microscopy  of  Technical  Products,  p.  74)  by  cautiously 
treating  flax  fibres  with  iodine  and  weak  sulphuric  acid  three  layers  may  be  dis- 
tinguished: first,  an  outer  dark-blue  layer  becoming  liquid  in  the  reagent;  second, 
a  longitudinally  striated  light-blue  tube;  and  third,  a  narrow  yellow  tube  with 
yellow  contents.  If  strong  sulphuric  acid  is  used  the  whole  cell-well  changes  to  a 
blue  swollen  mass,  and  only  the  inner  tube  containing  protoplasmic  remains 
persists  for  any  considerable  time.  In  cuprammonia  the  cellulose  wall  goes  into 
solution  with  the  formation  of  a  blue  color  and  bladder-like  swellings,  while  the 
inner  tube  remains  as  a  sinuous  and  in  parts,  almost  curled  thread. 


LINEN  393 

stand  the  action  of  the  reagent  the  longest  and  remain  floating 
in  the  liquid,  like  the  cuticle  of  cotton.  Parenchymous  and 
intercellular  matter  adhering  to  the  fibre  also  remains  undis- 
solved  in  the  reagent. 

The  color  of  the  best  varieties  of  flax  is  a  pale  yellowish 
white.  Flax  retted  by  means  of  stagnant  water,  or  by  dew, 
is  a  steel  gray,  and  Egyptian  flax  is  a  pearl  gray.  The  pale 
yellow  color  of  flax  is  due  to  a  natural  pigment,  but  the  other 
color  arises  from  the  decomposition  of  the  intercellular  matter, 
which  is  left  as  a  stain  on  the  fibre.  Flax  that  has  been  imper- 
fectly retted  shows  a  greenish  color.  The  natural  color  of  linen 
is  readily  bleached  by  solutions  of  chloride  of  lime  in  a  manner 


FIG.    84.— Cell   of   Flax    Fibre   Treated   with    Schweitzer's   Reagent.     (X4oo.) 
Showing  insoluble  cuticle  of  inner  canal.     (After  Wiesner.) 

similar  to  the  bleaching  of  cotton.  But  the  linen  fibre  suffers 
considerable  deterioration  thereby.  There  are  four  grades  of 
linen-bleaching — quarter,  half,  three-quarters,  and  full  bleach. 
The  whiter  the  fibre  is  bleached  the  weaker  it  becomes.* 

The  lustre  of  linen  is  quite  pronounced  and  almost  silky  in 
appearance;  flax  that  is  overretted  is  dull  in  appearance. 
Egyptian  flax  is  also  dull,  due  to  the  cells  being  coated  with 
residual  intercellular  matter.  | 

*  In  determining  the  size  (or  number)  of  bleached  linen  yarns,  the  loss  in  bleach- 
ing is  fixed  at  20  per  cent  for  full,  18  per  cent  for  three-quarters,  and  15  per  cent 
for  one-half  bleach. 

f  Hanausek  (Microscopy  of  Technical  Products,  p.  77)  gives  a  microscopical 
method  of  distinguishing  between  linen  and  tow  yarns,  as  follows: 

1.  Linen  yarn  consists  of  fibre  cells  which  mostly  have  narrow  lumens  and 
pointed  ends,  and  is  mostly  free  from  other  tissues  of  the  stem. 

2.  Tow  yarn  consists  of  fibre  cells  with  both  narrow  and  broad  lumens,  and 
always  contains  epidermal  cells. 

Herzog  also  points  out  that  fibres  which  he  designates  as  "  unripe  "  occur 


394  THE  TEXTILE  FIBRES 

The  flax  fibre  is  much  stronger  than  that  of  cotton,  though 
overretted  flax  is  brittle  and  weak.* 

As  flax  is  a  better  conductor  of  heat  than  cotton,  linen  fabrics 
always  feel  colder  to  the  touch  than  those  made  from  cotton. 

The  bast-cells  of  the  flax  fibre  may  be  isolated  by  treatment 
with  a  dilute  chromic  acid  solution.  They  are  cylindrical  in 
form  and  taper  to  a  point  at  each  end.  At  the  middle  they 
measure  12  to  26  ^,  with  an  average  of  about  15  [JL.|  The 
length  varies  from  4  to  66  mm.,  with  an  average  of  about  25 
mm.  The  ratio  of  the  length  of  the  cell  to  its  breadth  is  about 
1200.  Under  the  microscope  the  surface  of  the  cell  appears 
smooth  or  marked  longitudinally,  with  frequent  transverse 
fissure  lines  and  jointed  structures.  On  treatment  with  chlor- 
iodide  of  zinc  the  latter  are  colored  much  darker  than  the  rest 
of  the  cell  and  are  thus  rendered  more  apparent.  The  lumen 
appears  in  the  centre  of  the  cell  as  a  narrow  yellow  line,  and  it 
is  usually  completely  filled  with  protoplasm.  With  iodin  and 
sulphuric  acid  linen  gives  a  blue  color,  which,  however,  develops 
less  quickly  than  with  cotton;  with  tincture  of  madder  an 
orange  color  is  produced,  while  fuchsin  (followed  with  ammonia) 
gives  a  permanent  rose  color  in  contradistinction  to  cotton. 
These  tests,  however,  are  only  applicable  to  unbleached  linen, 
for  the  cellulose  of  bleached  linen  shows  little  or  no  chemical  dif- 
ference from  that  of  cotton.  In  cross-section  the  cells  of  flax  are 
polygonal,  with  rounded  edges,  show  a  small  lumen,  and  a  rela- 
tively thick  cell-wall  (see  Fig.  85).  In  these  respects  they  are 
very  similar  to  hemp,  but  may  be  distinguished  from  the  latter, 
however,  in  that  they  do  not  aggregate  in  thick  bundles,  but  are 
more  or  less  isolated  from  each  other,  so  that  the  cross-section 
frequently  shows  but  one  cell,  and  seldom  more  than  three  or 
four. 

in  tow.  These  fibres  are  from  the  upper  part  of  the  flax  stems  and  have  broad 
lumens  with  abundant  remains  of  protoplasmic  contents. 

*  According  to  Spon,  samples  of  flax  fibre  exposed  for  two  hours  to  steam  at 
2  atmospheres,  boiled  in  water  for  three  hours,  and  again  steamed  for  four  hours, 
lost  only  3.5  per  cent  in  weight,  while  Manila  hemp  under  these  conditions  lost 
6.07,  hemp  6.18  to  8.44,  and  jute  21.39  per  cent. 

t  According  to  Vetillard,  15  to  37  [x,  with  an  average  of  22  JJL. 


LINEN 


395 


Other  differences  from  hemp  exhibited  by  the  linen  fibre 
are:  (a)  the  cross-section  does  not  show  an  external  yellow 
layer  of  lignin  when  treated  with  iodin  and  sulphuric  acid; 
(b)  it  gives  reactions  for  pure  cellulose  only,  that  is,  iodin  and 
sulphuric  acid  color  the  fibre  a  pure  blue,  and  anilin  sulphate 
gives  no  color,  though  at  times  there  are  shreds  of  parenchymous 
tissue  present  which  are  colored  yellow  by  this  latter  reagent  and 
appear  to  be  lignified ;  (c)  the  lumen  of  the  hemp  fibre  is  seldom 
filled  with  yellowish  protoplasm  like  that  of  the  linen  fib  re;  (d)  the 
linen  fibres  end  in  sharp  points,  whereas  those  of  hemp  do  not. 


A    I 


E 


FIG.  85. — Flax  Fibre.     (Xsoo.)     A,  longitudinal  view,  showing  jointed  structure 
and  tracing  of  lumen;  B,  cross-sections. 

The  following  analyses  show  the  composition  of  two  typical 
specimens  of  flax  (H.  Mliller). 


I. 
Per  Cent. 

II. 
Per  Cent. 

Water  (hygroscopic)  

8.65 

10.70 

Aqueous  extract  
Fat  and  wax            

3.65 
2    3Q 

6.  02 
2    37 

Cellulose 

82    $7 

nro 

Ash  (mineral  matter)  *  ... 

o.  70 

1.32 

Intercellular  matter  

2.74 

9.41 

*  According  to  Wiesner,  the  ash  of  the  linen  fibre  amounts  to  from  1.18  to 
5.93  per  cent,  and  shows  no  evidence  of  crystals. 


396 


THE  TEXTILE  FIBRES 


The  flax  fibre  contains  a  certain  wax-like  substance,  vary- 
ing in  amount  from  0.5  to  2  per  cent.  It  may  be  extracted 
from  the  fibre  by  means  of  benzene  or  ether.  The  color  of 
the  wax  varies  with  that  of  the  flax  from  which  it  is  obtained . 
It  has  a  rather  unpleasant  odor,  resembling  flax  itself.  Its 
melting-point  is  61.5°  C.,  and  its  specific  gravity  at  60°  F.  is 
0.9083.  According  to  Hoffmeister,  this  wax  consists  of  81.32 
per  cent  of  unsaponifiable  waxy  matter  and  18.68  per  cent 


FIG.  86.— Flax  Fibre.     (Xaoo.)    Stained  with  Methyl  Violet.  /,  joint-like  forma- 
tions; F,  fissure-like  markings.     (Micrograph  by  author.) 

of  saponifiable  oil.  Of  the  latter,  54.49  per  cent  is  free  fatty 
acid.  The  waxy  matter  has  a  melting-point  of  68°  C.,  and 
apparently  is  a  mixture  of  several  bodies.  The  principal  one 
resembles  ceresin,  and  there  are  also  present  ceryl  alcohol 
and  phylosterin.  The  saponifiable  matter  appears  to  contain 
small  quantities  of  soluble  fatty  acids,  like  caproic,  stearic, 
palmitic,  oleic,  linolic,  linolenic,  and  isolinolenic. 

Highly  purified  flax  appears  to  approximate  very  closely 


LINEN  397 

to  both  the  composition  and  chemical  properties  of  cotton.  The 
ordinary  flax  fibre  of  trade  may  be  said  to  contain  about  5  per 
cent  less  of  cellulose  than  cotton,  there  being  about  that  much 
more  impurity  present  in  the  form  of  intercellular  matter  and 
pectin  bodies.  Linen,  however,  appears  to  be  free  from  woody 
or  lignified  tissue,  as  it  gives  none  of  the  reactions  for  these.* 
The  linen  fibre  swells  up  greatly  when  treated  with  an  ammoniacal 
solution  of  copper  oxide,  but,  unlike  cotton,  it  does  not  exhibit 
the  peculiar  sausage-shaped  appearance,  nor  does  it  dissolve 
completely.  The  hygroscopic  moisture  in  linen  is  about  the 
same  as  in  cotton;  in  fact,  all  vegetable  fibres  appear  to  con- 
tain approximately  the  same  amount  (from  6  to  8  per  cent). 

The  amount  of  "  regain  "  allowed  in  the  conditioning  of 
linen  at  Roubaix  is  from  10  to  12  per  cent.  Wiesner  gives  the 
amount  of  hygroscopic  moisture  in  linen  as  5.7  to  7.22  per  cent. 
The  Turin  Congress  fixed  the  regain  for  linen  at  12  per  cent. 

Due  to  differences  in  structure,  linen  is  more  easily  disinte- 
grated than  cotton,  and  consequently  does  not  withstand  the 
action  of  boiling  alkaline  solutions,  solutions  of  bleaching  pow- 
der, or  other  oxidizing  agents,  etc.,  as  well  as  cotton. 

Toward  mordants  and  dyestuffs,  etc.,  linen  does  not  react 
as  readily  as  cotton,  hence  its  manipulation  in  dyeing  is  more 
difficult  In  general,  however,  it  may  be  said  that  the  dyeing 
and  treatment  of  linen  are  practically  the  same  as  with  cotton. 

The  oil-wax  group  of  constituents  in  the  flax  fibre  plays  an 
important  part  in  the  spinning  of  this  fibre,  and  the  failure  of 
many  of  the  artificial  processes  of  retting  flax  may  be  attributed 
to  the  fact  that  the  fibre  is  left  with  a  deficiency  of  these  con- 
stituents.! In  the  breaking  down  of  the  cuticular  celluloses, 

*  Hohnel  has  shown,  however,  there  are  short  spaces  on  the  fibre  which  are 
strongly  lignified.  Most  of  this  lignin  is  removed  by  bleaching. 

t  Hoffmeister  (Berichte,  1903,  p.  1047)  has  shown  that  the  odor  and  suppleness 
of  flax  are  due  to  a  characteristic  wax  on  the  surface  of  the  fibre,  and  if  this  wax 
is  removed  by  suitable  solvents,  the  fibre  becomes  rough,  lustreless,  and  brittle. 
This  wax  is  insoluble  in  water,  has  a  sp.gr.  of  0.9083  (at  15°  C.)  and  melts  at  61.5° 
C.  It  consists  chiefly  of  a  paraffin  resembling  ceresin  mixed  with  glycerides  of 
several  fatty  acids.  It  also  contains  phytosterol  and  ceryl  alcohol,  and  a  small 
proportion  of  a  volatile  aldehydic  substance.  The  so-called  "  flax-dust  "  in 
linen  factories  was  found  to  contain  10  per  cent  of  the  wax. 


398  THE  TEXTILE   FIBRES 

whether  in  the  retting  or  in  the  bleaching  processes,  these  waxes 
and  oils  are  separated.  Their  complete  elimination  from  the 
cloth  necessitates  a  very  elaborate  treatment,  such  as  is  repre- 
sented by  the  "  Belfast  Linen  Bleach," 

Linen  yarns  are  known  as  hand-spun  or  machine-spun; 
the  former  are  softer  and  smoother  and  more  elastic,  but  uneven 
and  less  rounded  in  form,  while  machine-spun  yarns  are  stiff 
and  rough,  but  of  uniform  thickness  and  perfectly  round. 
According  to  the  method  of  spinning,  linen  yarns  are  also 
known  as  dry-spun  or  wet-spun;  the  former  have  greater  firm- 
ness, but  higher  numbers  can  be  obtained  by  wet-spinning. 
Tow  yarns  are  prepared  from  waste,  and  are  characterized  by 
numerous  knots  due  to  particles  of  shives.  In  the  English 
system,  the  counts  of  linen  yams  are  expressed  by  the  number 
of  leas  in  a  pound,  each  lea  measuring  300  yards.  To  obtain  the 
count  of  cotton  yarn  corresponding  to  the  count  of  linen  yarn, 
the  latter  number  is  divided  by  2.8.  In  the  French  system, 
the  count  of  linen  yarns  is  the  number  of  hanks  of  1000  metres 
contained  in  500  grams.  In  the  Austrian  system,  the  count 
indicates  the  number  of  hanks  to  10  English  pounds,  each  hank 
containing  3600  ells  (i  ell  =30.68  inches). 


CHAPTER  XVII 

JUTE,   RAMIE,    HEMP,    AND    MINOR   VEGETABLE    FIBRES 

i.  Jute  is  a  fibre  obtained  from  the  bast  of  various  species 
of  corchorus,  growing  principally  in  India  and  the  East  Indian 
Islands.*  The  most  important  variety  is  Corchoms  capsularis 
or  Jew's  mallow,  which  is  grown  throughout  tropical  Asia  not 
only  as  a  fibre  plant,  but  also  as  a  vegetable.  Other  varieties 
are  C.  olitorius,  C.  fuscus,  and  C.  decemangulatus ;  the  latter  two 
however,  yield  but  a  small  proportion  of  the  jute  fibre  to  be  found 
in  trade,  t 

The  jute  plant  grows  to  a  height  of  from  10  to  12  feet  and 
its  fibrous  layer  is  very  thick,  so  that  it  yields  from  two  to  five 
times  as  much  fibre  as  flax. 

The  Cor  chorus  capsularis  is  an  annual  plant,  growing  from 
5  to  10  feet  in  height,  with  a  cylindrical  stalk  as  thick  as  a  man's 
finger,  and  seldom  branching  near  the  top.  The  leaves,  which 

*  Jute  was  first  introduced  into  Europe  about  the  year  1795.  It  has  been 
used  for  spinning  since  1830.  At  the  present  time  there  is  more  jute  used, 'weight 
for  weight,  than  any  other  textile  fibre. 

f  The  commercial  fibre  known  as  Chinese  jute  is  not  a  variety  of  jute  at  all, 
but  is  derived  from  Abutilon  avicennce  or  Indian  mallow.  The  latter  grows 
extensively  as  a  weed  in  America.  The  bast  fibre  is  white  and  glossy,  and  has 
considerable  tensile  strength.  It  is  also  used  for  the  making  of  paper  stock. 
Chemically  it  appears  to  consist  of  bastose,  and  hence  resembles  jute  in  its  behavior 
toward  dyestuffs.  The  plant  produces  about  20  per  cent  of  fibre,,  but  is  of  doubtful 
economic  value.  Another  somewhat  similar  variety  is  the  Abutilon  incamim, 
which  grows  in  Mexico;  it  is  said  that  the  Indians  used  the  fibre  from  this  plant 
for  making  hammocks,  ropes,  and  nets,  which  are  so  durable  that  they  last  from 
seven  to  ten  years  in  constant  use.  There  are  also  several  East  Indian  species, 
of  Abutilon,  among  which  may  be  named  A.  indicum,  A.  graveolens,  A.  muticum, 
and  A,  polyandrum,  all  of  which  are  fibre  plants  suitable  chiefly  for  cordage;  the 
latter  yields  a  long  silky  fibre  resembling  hemp.  The  A .  periplocifolium,  growing 
in  tropical  America,  yields  a  very  good  bast  fibre,  quite  long,  and  of  a  creamy 
yellow  color. 

399 


400 


THE  TEXTILE  FIBRES 


are  of  light  green  color,  are  from  4  to  5  inches  long  by  i  ^  inches 
broad  toward  the  base,  but  tapering  upward  into  a  long  sharp 
point  with  edges  cut  into  saw-like  teeth,  the  two  teeth  next 
the  stalk  being  prolonged  into  thistle-like  points.  The  flowers 
are  small  and  of  a  yellowish  white  color,  coming  out  in  clusters 
of  two  or  three  together  opposite  the  leaves.  The  seed-pods 
are  short  and  globular,  rough  and  wrinkled  (see  Fig.  87  A).  The 


FIG.  87. — A,  seed-vessels  of  Corchorus  capsularis;    B,  seed-vessels  of  Corchorus 
olitorius.     (After  Bulletin  U.  S.  Dept.  Agric.) 

C.  olitorius  is  precisely  like  the  former  in  general  appearance, 
shape  of  leaves,  color  of  flower,  and  habits  of  growth;  but  it 
differs  entirely  in  the  formation  of  the  seed-pod,  which  is 
elongated,  almost  cylindrical,  and  of  the  thickness  of  a  quill 
(see  Fig.  87  B). 

The  preparation  of  the  fibre  from  the  jute  plant  is  a  rather 
simple  operation.  The  plant  is  usually  cut  while  in  bloom 
and  the  stalks  are  freed  from  leaves,  seed-capsules,  etc.,  and 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     401 

retted  by  steeping  in  a  sluggish  stream  of  water.  After  a  few 
days  the  bast  becomes  disintegrated,  and  the  retted  stalks  are 
pressed  and  scutched.  The  fibre  so  obtained  is  remarkably 
pure  and  free  from  adhering  woody  fibre  and  other  tissue. 
The  prepared  fibre  usually  has  a  length  of  from  4  to  7  feet,* 
possesses  a  pale  yellowish  brown  color,  though  the  best  qualities 
are  pale  yellowish  white  or  silver  gray,  and  exhibits  considerable 
lustre  and  tensile  strength.  The  ends  of  the  plant,  together 
with  the  various  short  waste  fibres,  appear  in  trade  under  the 
name  of  "  jute  butts"  or  "  jute  cuttings,"  and  are  employed 
as  a  raw  material  for  paper-manufacturing. 


FIG.  88. — Jute  Fibre.     (X300.)     a,  cross-sections;  b,  longitudinal  views;  c,  ends. 
(After  Cross  and  Bevan.) 

Kerrf  enumerates  the  following  varieties  of  jute  as  being 
the  most  common  in  trade :{  (a)  Uttariya,  or  northern  jute, 
by  far  the  best  variety,  as  it  possesses  the  best  qualities  as 
regards  length,  color,  and  strength;  it  is  never  equal  to  the 
Desi  and  Deswal  varieties,  however,  in  softness,  (b)  Deswal, 
which  is  next  in  commercial  value,  is  chiefly  desirable  on  account 
of  its  softness,  fineness,  bright  color,  and  strength,  (c)  Desi 
jute  has  a  long,  fine,  soft  fibre,  but  it  has  the  defects  of  being 

*  The  fibre  from  C.  capsularis  is  generally  longer  than  that  from  C.  olitorius. 
f  Report  on  Jute  in  Bengal,  1874. 

t  The  trade  names  for  the  different  qualities  of  jute  are  fine,  medium,  common, 
poor,  rejections,  and  cuttings. 


402 


THE  TEXTILE   FIBRES 


fuzzy  and  of  a  bad  color,  (d)  Deora  jute  is  strong,  coarse, 
black,  and  rooty,  and  is  much  overspread  with  runners;  it  is 
used  for  the  manufacture  of  rope,  (e)  Narainganji  jute  is  very 
good  for  spinning,  being  soft,  strong,  and  long;  but  the  fibre 
as  it  appears  in  trade  has  a  foxy-brown  color  which  detracts 
from  its  value,  though  this  defect  is  apparently  due  to  imper- 
fect steeping.  (/)  Bakrabadi  excels  particularly  in  color  and 
softness,  (g)  Bhatial  jute  is  very  coarse,  but  strong,  and  is  in 
demand  for  the  manufacture  of  rope,  (h)  Karimganji  is  a 
fine  variety,  long,  very  strong,  and  of  good  color,  (i)  Mir- 
ganji  is  of  medium  quality.  (/)  Jangipuri  jute  is  of  short 
fibre,  weak,  and  of  a  foxy  brown  color,  and  not  suitable  for  spin- 
ning.* 

According  to  Hohnel,  the  bast-cells  of  the  jute  fibre  are  from 
1.5  to  5  mm.  in  length,  and  from  20  to  25  ^  in  thickness,  the  mean 
ratio  of  the  length  to  the  breadth  being  about  90;  consequently 
the  elements  of  the  jute  fibre  are  relatively  short.     In  cross- 
section  the  jute  fibre  shows  a  bundle  of 
several  elements  bound  together;   these  are 
more  or    less  polygonal  in  outline,  with 
sharply    defined     angles.      Between     the 
separate  elements  is  a  narrow  median  layer 
(see  Figs.  88  and  90),  which,  however,  does 
not  give  a  much  darker  color  with  iodin 
and  sulphuric  acid  than  the  cell-wall  itself. 
The  lumen  is  about  as  wide,  or  at  times 
even    wider,  than    the    cell-wall,    and    in 
cross-section    is   round    or   oval.      Longi- 
tudinally   the    lumen    shows    remarkable 
constrictions    or    irregular   thicknesses   in 
e        reu  the  cell-wall  (see  Fig.  89),  though  toward 

(Micrograph 

by  author.)  the   end  of  the  fibre  the  lumen  broadens 

out  considerably,  causing  the  cell-wall  to 
become  very  thin.     Externally  the  fibre  is  smooth  and  lustrous, 

*  Jute  is  often  called  by  the  name  Calcutta  hemp,  owing  to  the  fact  that  most 
of  the  commercial  jute  passes  through  Calcutta.  It  is  mostly  exported  in  the 
unbleached  condition. 


Fibre 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     403 

and  has  no  jointed  ridges  or  transverse  markings,  such  as  seen 
in  linen  or  most  other  bast  fibres. 

Miiller  gives  the  following  method  for  the  isolation  of  pure 
cellulose  from  jute:  Two  grams  of  the  material  are  dried  at 
from  no0  to  115°  C.  In  order  to  remove  wax,  etc.,  it  is  next 


FIG.  90. — Cross-section  of  Jute-straw.  Showing  transverse  section  of  portion  of 
bast  only,  giving  the  anatomy  of  the  fibrous  tissue,  the  form  of  the  bast- 
cells,  and  the  thickening  of  the  cell-walls.  (Cross  and  Bevan.) 

treated  with  a  mixture  of  alcohol  and  benzol,  and  is  subse- 
quently boiled  with  very  dilute  ammonia  water.  The  softened 
mass  is  then  pulverized  in  a  mortar,  and  placed  in  a  large,  glass- 
stoppered  flask  with  100  cc..  of  water.  From  5  to  10  c.c.  of  a 
solution  of  2  c.c.  of  bromin  in  500  c.c.  of  water  are  added 
until  a  permanent  yellow  is  obtained  after  standing  twelve 


404 


THE  TEXTILE  FIBRES 


to  twenty-four  hours.  The  substance  is  then  filtered,  washed 
with  water,  and  heated  to  boiling  with  water  containing  a  little 
ammonia.  After  this  it  is  filtered,  washed,  and  again  treated 
with  the  bromin  solution,  as  above  indicated,  until  a  permanent 
yellow  color  is  obtained.  The  fibre  is  then  boiled  with  dilute 
ammonia,  and  on  filtering  and  washing  leaves  a  residue  of  pure 
white  cellulose. 

In  its  chemical  composition  jute  is  apparently  quite  different 
from  linen  and  cotton,  being  composed  of  a  modified  form  of 
cellulose  known  as  lignocellulose  or  bastose.  Bastose,  properly 
speaking,  is  a  compound  of  cellulose  with  lignin.  It  behaves 
quite  differently  from  cellulose  toward  various  reagents,  its 
chief  distinction  being  that  it  is  colored  yellow  by  iodin  and 
sulphuric  acid,  whereas  pure  cellulose  is  colored  blue.  With 
dilute  chromic  acid,  to  which  a  little  hydrochloric  acid  has  been 
added,  jute  gives  a  blue  color.  When  treated  with  an  ammoniacal 
solution  of  copper  oxide  the  fibres  swell  considerably,  but  do 
not  readily  dissolve.  With  chlor-iodide  of  zinc  jute  gives  a 
yellow  color.  The  following  table  gives  the  principal  reactions 
used  to  distinguish  cellulose  from  bastose:* 


Reagent. 

Cellulose. 

Bastose. 

Iodin  and  sulphuric  acid  .  . 
Anilin    sulphate    and    sul- 
phuric acid 

Blue  color 
No  change 

Yellow  to  brown  color 
Deep-yellow  color 

Basic  dyestuffs  

No  change 

Becomes  colored 

Weak  oxidizing  agents  .... 
Schweitzer's  reagent    . 

No  change 
Quickly  dissolves 

Quickly  decomposes 
Swells,  becomes  blue,  and 

slowly 

dissolves 

A  solution  of  ferric  ferricyanide  f  colors  ligno-cellulose  a 
deep  blue,  owing  to  the  deoxidation  of  the  ferric  compound  by 

*  According  to  Cross  and  Be  van,  the  jute  fibre  may  be  regarded  as  an  anhydro- 
aggregate  of  three  separate  compounds:  (a)  A  dextrocellulose  allied  to  cotton, 
(b)  a  pentacellulose  yielding  furfural  and  acetic  acid  on  hydrolysis;  (c)  lignone, 
a  quinone  which  is  converted  by  chlorination  and  reduction  into  derivatives  of 
the  trihydric  phenols. 

t  This  is  the  green  solution  resulting  from  the  interaction  of  solutions  of  ferric 
chloride  and  potassium  ferricyanide. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     405 


the  lignone.  This  reaction  is  useful  in  following  the  progressive 
elimination  of  the  lignone  constituents  in  the  isolation  of  pure 
cellulose  from  jute,  etc. 

Analysis  of  jute  shows  it  to  consist  of  the  following: 


Constituents. 

Nearly  Color- 
less Specimen. 

Fawn-colored 
Fibre. 

Brown 
Cuttings. 

Ash  

0.68 

Water  (hygroscopic)*  
Aqueous  extract 

9-93 
i  03 

9.64 
I   63 

12.58 
1   04- 

Fat  and  wax 

O    3Q 

O    32 

O  4<C 

Cellulose  
Incrusting  and  pectin  matters. 

64.24 
24    41 

63-05 

2S    36 

61.74 
21    20 

The  ash  of  jute  consists  principally  of  silica,  lime,  and  phos- 
phoric acid;  manganese  is  nearly  always  present  in  small  amount. 
The  ash  in  completely  dry  jute  varies  from  0.9  to  1.75  per  cent. 

Bastose  is  dissolved  by  the  usual  cellulose  solvents,  such  as 
zinc  chloride  and  Schweitzer's  reagent;  and  from  these  solutions 
the  lignocellulose  may  be  precipitated  by  dilution  or  acidifying 
respectively,  though  the  precipitation  is  never  complete,  there 
remaining  in  solution  from  10  to\25  per  cent  of  the  original 
substance. 

The  chief  chemical  difference  between  jute  and  the  pure 
cellulose  fibres  f  is  in  the  ability  of  the  former  to  combine 
directly  with  basic  dyestuffs.  In  fact  it  acts  in  this  respect 
similar  to  cotton  which  has  been  mordanted  with  tannic  acid. 
Jute  is  also  more  sensitive  to  the  action  of  chemicals  in  general 
than  cotton. or  linen.  On  this  account  it  cannot  be  bleached 
with  much  success,  as  treatment  with  alkalies  and  bleaching 

*  According  to  Wiesner,  fresh  jute  contains  about  6  per  cent  of  hygroscopic 
moisture  and  brown  jute  about  7  per  cent.  When  completely  saturated  with 
moisture  the  former  will  contain  about  23  per  cent  and  the  latter  24  per  cent. 
The  Turin  Congress  adopted  a  regain  of  13!  per  cent  for  the  conditioning 
of  jute. 

t  When  jute  is  hydrolyzed  by  heating  with  i  per  cent  sulphuric  acid  in  an 
autoclave  to  110°  C.  small  quantities  of  formic  and  acetic  acids  are  produced. 
Under  similar  conditions  cotton  does  not  yield  these  acids.  Cross  (Berichte, 
1910,  p.  1526)  consequently  considers  that  the  ligno-cellulose  molecule  contains 
formyl  and  acetyl  groups. 


406 


THE  TEXTILE  FIBRES 


powder  weakens  and  disintegrates  the  fibre  to  a  considerable 
extent.* 

The  jute  fibre  is  relatively  weak  when  compared  with 
other  bast  fibres,  and  the  chief  reasons  for  its  prominence  among 
the  textile  fibres  are  its  fineness,  silk-like  lustre,  and  adaptability 
for  spinning.  The  plant  is  also  easy  to  cultivate,  and  returns 
a  large  yield  of  fibre.  The  chief  defect  of  jute  is  its  lack  of 
durability;  when  exposed  to  dampness  it  rapidly  deteriorates; 


FIG.  91. — Jute  Fibre.     (Xsoo.)     L,  lumen;    C,  constrictions  in  lumen;    E,  end 
of  fibre.     (Micrograph  by  author.) 

and  even  under  ordinary  conditions  of  wear,  the  fibre  gradually 
becomes  brittle  and  loses  much  of  its  strength.     The  bleached 

*  Samples  of  jute  fibre  exposed  for  two  hours  to  steam  at  2  atmospheres,  fol- 
lowed by  boiling  in  water  for  three  hours,  and  again  steamed  for  four  hours,  lost 
21.39  Per  cent  by  weight,  being  about  three  times  as  great  a  loss  as  that  suffered 
by  hemp,  Manila  hemp,  phormium,  and  coir.  A  similar  test  for  jute  with  flax 
hemp,  ramie,  and  other  fibres  showed  as  great  a  loss,  while  flax  lost  less  than  4 
per  cent  and  ramie  a  small  fraction  under  i  per  cent. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     407 

fibre  is  especially  liable  to  such  deterioration;*  it  gradually 
loses  its  whiteness,  and,  evidently  due  to  oxidation,  becomes 
dingy  and  yellowish  brown  in  color. 

Jute  is  principally  used  for  the  making  of  coarse  woven 
fabrics,  such  as  gunny  sacks  and  bagging,  where  cheapness  is 
of  more  consequence  than  durability,  f  It  also  finds  considerable 
use  in  the  tapestry  trade,  being  used  as  a  binding- thread  in 
the  weaving  of  carpets  and  rugs.  On  account  of  its  high  lustre 
and  fineness,  it  is  also  adapted  for  the  preparation  of  cheap 
pile  fabrics  for  use  in  upholstery.  Of  late  years  a  variety  of 
novelty  fabrics  for  dressgoods  have  also  been  made  from  jute, 
used  in  conjunction  with  woolen  yarns.}  Jute  has  also  been 
used  extensively  as  a  substitute  for  hemp,  for  which  purpose 
the  former  is  rendered  very  soft  and  pliable  by  treatment  with 
water  and  oil.  A  mixture  of  20  parts  of  water  with  2.5  parts 
of  train-oil  is  sprinkled  over  100  parts  of  jute  fibre.  It  is  left 
for  one  to  two  days,  then  squeezed  and  heckled,  whereby  the 
fibres  become  very  soft  and  isolated.  Jute  is  also  largely 
used  in  the  manufacture  of  twine  and  smaller  sizes  of  rope. 
Owing  to  its  cheapness,  it  is  used  to  adulterate  other  more 
valuable  fibres,  but  due  to  its  tendency  to  rapid  deterioration, 
its  use  in  this  connection  should  not  be  encouraged.  The 
"  jute  butts  "  and  miscellaneous  waste  are  extensively  em- 
ployed as  a  raw  material  in  the  manufacture  of  paper. 

2.  Lignocellulose. — Jute  differs  somewhat  from  the  pre- 
viously considered  vegetable  fibres  in  that  it  does  not  consist 
of  comparatively  pure  cellulose,  but  contains  a  large  amount 
of  modified  cellulose  known  as  lignocellulose.§  As  this  latter 

*  It  must  be  borne  in  mind  that  the  jute  fibre  is  a  ligno-cellulose  composed  of 
cellulose  units  about  |  inch  in  length  cemented  together  by  lignone  components. 
In  bleaching  processes  where  a  full  white  is  obtained,  these  lignone  subtances 
are  removed  and  this  leads  to  the  structural  disintegration  of  the  fibre. 

t  Jute  is  the  cheapest  fibre  used  in  American  textile  manufacturing,  and  it  is 
employed  in  greater  quantities  than  any  other  except  cotton  and  sisal. 

J  The  waste  arising  in  the  spinning  of  jute  mixed  with  similar  waste  from 
linen  and  hemp  is  manufactured  into  a  product  known  as  Kosmos  fibre  or  artificial 
wool. 

§  The  formation  of  lignocellulose  is  to  be  considered  as  a  process  of  thickening 
by  incrustation,  and  recent  researches  in  this  matter  indicate  this  incrustation 


408 


THE  TEXTILE  FIBRES 


compound  differs  essentially  both  in  its  chemical  composition 
and  reactions  from  ordinary  cellulose,  it  will  be  of  immediate 
interest  to  make  a  study  of  this  product,  not  only  in  connection 
with  its  direct  association  with  jute,  but  also  as  a  general  sub- 
stance occurring  in  other  vegetable  fibres  as  well.  It  is  doubtful 
if  lignocellulose  can  be  regarded  as  a  a  simple  chemical  body, 
its  reactions  tending  to  indicate  that  it  is  a  complex  of  several 
different  bodies.  The  lignocellulose  of  jute  has  a  lower  per- 
centage of  oxygen  than  that  present  in  normal  cellulose,  as 
follows : 


Normal  Cellulose 
(Cotton). 
Per  Cent. 

Lignocellulose 
(Jute). 
Per  Cent. 

Carbon  
Hydrogen 

44-2 
6   a 

46-47 
61-58 

Oxygen  

49-5 

47.9-47.2 

There  are  two  distinct  chemical  differences  between  normal 
cellulose  and  lignocellulose:  (i)  Normal  cellulose  does  not 
react  with  chlorin,  whereas  lignocellulose  readily  combines  with 
chlorin  to  yield  definite  products:  *  (2)  normal  cellulose  does  not 
yield  furfural  whereas  lignocellulose  does,  thereby  indicating  the 
possibility  of  its  containing  an  oxycellulose  derivative,  f 

is  a  process  of  forming  adsorption  compounds;  the  colloidal  hydrated  celluloses 
at  first  elaborated  taking  up  soluble  colloidal  products  from  solution  in  the  cam- 
bium fluids  (Wislicenus,  Zeitsch.  Kolloide,  1910,  p.  17).  Chemically  the  forma- 
tion of  lignin  is  to  be  regarded  as  a  combination  of  cellulose  with  acid  and  un- 
saturated  ketonic  groups.  Conversely,  processes  which  attack  these  groups 
resolve  the  lignin  into  soluble  derivatives  and  cellulose  which  is  resistant  and  insol- 
uble. The  separation  of  the  cellulose  is  attended  by  disintegration,  and  the 
fibre  is  resolved  into  its  component  cell  units,  which  are  usually  2  to  3  mm.  in 
length  and  0.02  to  0.03  mm.  in  diameter.  The  elimination  of  the  non-cellulose 
constituents  is  also  attended  by  considerable  loss  in  weight.  In  jute  the  amount 
of  cellulose  is  about  70  to  80  per  cent,  and  the  lignone  about  30  to  20  per  cent. 

*  Lignone  reacts  quantitatively  with  chlorin,  combining  in  a  characteristic 
and  invariable  proportion.  In  the  case  of  jute  this  proportion  is  8  per  cent  of 
the  ligno  cellulose. 

t  The  cellulose  and  lignocellulose  in  jute  and  similar  fibres  may  be  separated 
by  a  treatment  with  chlorin,  the  lignocellulose  combining  with  chlorin  to  yield 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     409 

Lignocellulose  also  reacts  with  several  aromatic  compounds 
to  give  colored  bodies.  With  phloroglucinol  and  hydrochloric 
acid  it  gives  a  crimson  color,  with  phenylhydrazine  a  yellow 
color,  and  with  dimethylparaphenylenediamine  a  crimson  color.* 


a  product  soluble  in  a  solution  of  sodium  bisulphite.  Cross  and  Bevan  described 
the  following  method  of  procedure.  A  weighed  amount  (5  grams)  of  the  fibre  is 
dried  in  a  water-oven,  and  then  boiled  with  a  i  per  cent  solution  of  caustic  soda 
for  thirty  minutes.  The  mass  is  then  removed,  and  after  pressing  out  most  of 
the  liquid  it  retains,  it  is  treated  with  a  current  of  chlorin  gas  for  one-half  to  one 
hour.  It  is  then  washed  and  slowly  heated  with  a  2  per  cent  solution  of  sodium 
bisulphite.  When  the  liquid  reaches  the  boiling  point,  0.2  per  cent  of  caustic 
soda  is  added,  and  the  boiling  allowed  to  proceed  for  five  minutes.  The  residue 
consists  of  nearly  pure  cellulose.  It  is  washed  with  hot  water  and  further  purified 
by  a  few  minutes'  treatment  with  a  o.i  per  cent  solution  of  potassium  per- 
manganate, again  washed,  dried,  and  weighed.  Bromin  cannot  be  used  in  this 
reaction  in  place  of  chlorin  as  it  acts  on  the  cellulose  to  some  extent,  giving  a 
figure  for  lignocellulose  from  2  to  5  per  cent  higher. 

The  furfural  reaction  of  lignocellulose  is  obtained  by  heating  jute  with  dilute 
hydrochloric  acid.  Cross  and  Bevan  give  the  following  method  of  estimating 
furfural  in  jute:  A -weighed  portion  (5  grams)  of  the  fibre  is  heated  with  100  c.c. 
of  a  1 2  per  cent  solution  of  hydrochloric  acid  in  a  flask  connected  with  a  condenser 
and  the  tube  of  a  stoppered  separatory  funnel.  The  distillation  should  proceed  at 
the  rate  of  2  c.c.  per  minute,  and  successive  portions  of  30  c.c.  each  collected  until 
anilin  acetate  and  hydrochloric  acid  no  longer  yield  a  rose  coloration.  The 
distillate  is  then  treated  with  a  slight  excess  of  sodium  carbonate,  then  acidified 
with  acetic  acid,  and  made  up  to  a  definite  volume  with  sodium  chloride  solution 
containing  approximately  the  same  amount  of  salt  as  has  been  formed  in  the 
distillate.  It  is  next  treated  with  an  aqueous  solution  of  phenylhydrazine  con- 
taining 12  grams  of  the  latter  and  7.5  grams  of  acetic  acid  in  100  c.c.  The  pre- 
cipitated hydrazone  is  washed,  dried  in  a  vacuum  at  70°  C.,  and  weighed.  This 
weight  multiplied  by  the  factor  0.538  gives  the  amount  of  furfural. 

*  Cross,  Bevan  and  Briggs  (Chem.  Zeit.,  1907,  p.  725)  have  shown  that  there 
is  a  definite  absorption  of  phloroglucinol  by  lignocellulose,  and  the  following 
method  has  been  suggested  by  them  for  determining  this  absorption:  A  weighed 
quantity  (2  grams)  of  the  dried  fibre  is  mixed  with  40  c.c.  of  a  solution  of  2.5  grams 
of  phloroglucinol  in  100  c.c.  of  hydrochloric  acid  (sp.gr.  1.06).  After  standing 
for  twelve  hours  the  liquid  is  filtered  through  cotton;  10  c.c.  of  the  filtrate  are 
then  titrated  with  a  standard  solution  of  formaldehyde,  and  the  difference  between 
the  result  and  a  blank  titration  on  10  c.c.  of  the  original  phloroglucinol  solution 
gives  the  measure  of  the  absorption.  The  standard  solution  for  the  titration 
contains  2  grams  of  40  per  cent  formaldehyde  mixed  with  500  c.c.  of  hydrochloric 
acid  (sp.gr.  1.06).  The  10  c.c.  of  phloroglucinol  solution  are  diluted  with  20 
c.c.  of  the  hydrochloric  acid  and  heated  to  70°  C.,  and  the  aldehyde  solution  is 
added  at  the  rate  of  i  c.c.  every  two  minutes  until  all  the  phloroglucinol  has  been 
precipitated,  and  the  liquid  no  longer  gives  a  red  coloration  when  dropped  on  paper 


410  THE  TEXTILE   FIBRES 

Lignocellulose  also  reacts  with  the  bisulphites  of  the  alkali 
and  alkaline  earth  metals;  at  elevated  temperatures  and  under 
pressure  being  converted  quantitatively  into  cellulose  and  soluble 
sulphonated  products  of  lignone.  On  this  reaction  is  based  the 
manufacture  of  wood-pulp  by  the  sulphite  process.  Solutions  of 
caustic  soda  at  elevated  temperatures  also  attack  lignocellulose, 
separating  the  cellulose  and  giving  ill-defined  soluble  products 
of  lignone.  On  this  reaction  is  based  the  manufacture  of  soda- 
pulp. 

Hydriodic  acid  reacts  with  lignocelluloses  with  formation  of 
methyl  iodide.  The  estimation  of  this  latter  volatile  product 
is  taken  as  the  index  or  quantitative  measure  of  the  "  methoxy  " 
(OCHs)  groups  present  in  the  lignocellulose.  This  index  may 
also  be  considered  as  the  "  chemical  constant,  of  lignification." 
The  following  table  shows  these  constants  as  determined  for 
various  fibres: 

Per  Cent,  OCHs. 
Jute  ......................  .....................    1.87 

Cotton  ......................................  ,.   o.o 

Flax  ............  ..............................  o.o 

Hemp  .........................................   o  .  29 

China  grass  .....................................   0.07 

Sulphite  pulp  ..........  .  ........................   o  .  34 

Swedish  filter-paper  .................  ............   o.o 

3.  Ramie,  or  China  Grass,  is  a  fibre  obtained  from  the  bast 
of  the  stingless  nettle,  or  Bcehmeria.  Although  frequently 
confounded  in  trade,  ramie  and  China  grass  are  in  reality  two 
distinct  fibres.  The  former  (also  known  as  rhea)  is  obtained 
from  the  Bcehmeria  tenacissima,  which  grows  best  in  tropical 
and  subtropical  countries.  The  latter  is  obtained  from  Bcehmeria 
nivea,  which  grows  principally  in  the  more  temperate  climes.* 

containing   ground   wool   pulp    (newspaper).     This    test   yielded   the    following 
figures  for  phloroglucinol  absorption: 


»,   ,     •   , 
Material. 


Phloroglucinol  Absorbed. 
^er  Cent 


Wood  pulp  ......................................  7.5 

Jute  ............................................  4.2 

Esparto  cellulose  ..............  .  ..................  0.5 

Cotton  .........................................  0.2 

*  The  ramie  plant  is  of  more  robust  habit  and  has  larger  leaves,  which  are 
green  on  both  sides;  hence  the  name  green  ramie,  which  its  fibre  sometimes  receives 


JUTE,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE   FIBRES     411 

The  two  species,  however,  are  so  similar  in  nature,  and  the  fibres 
are  so  universally  confounded  with  one  another,  that  it  is  only 
possible  to  consider  them  as  a  single  substance,  which  will  be 
done  under  the  name  of  ramie.  The  plant  is  a  shrub,  reaching 
4  to  6  feet  in  height,  and  is  very  hardy.  It  is  cultivated  largely 
in  China  *  and  India,  and  has  also  been  grown  successfully 
in  America,  f 


FIG.  92. — Ramie  Fibre. 


(Xsoo.)     a,  sections;    b,  longitudinal  view;    c,  ends. 
(After  Cross  and  Bevan.) 


The  fibre  of  ramie  is  very  strong  and  durable,  probably 
ranking  first  of  all  vegetable  fibres  in  this  respect.  I  It  is  also 

in  trade.  The  China  grass  plant  has  leaves  which  are  white  felted  beneath; 
hence  the  name  white  ramie  sometimes  given  to  its  fibre. 

*  The  ramie  plant  in  China  is  known  as  Tchow  Ma,  and  is  extensively  cultivated 
for  its  fibre.  From  8000  to  10,000  tons  of  fibre  annually  are  exported  to  Europe, 
which  received  most  of  its  supply  from  this  source.  In  Cochin  China  ramie  is 
known  as  Cay-gal,  in  Bengal  as  Kankura. 

f  The  use  of  China  grass  or  ramie  was  probably  known  to  the  Chinese  at  a 
very  early  period;  some  writers  have  also  attempted  to  show  that  it  was  used  in 
Egypt  several  thousand  years  ago  contemporaneously  with  flax  for  the  prepara- 
tion of  mummy-cloths. 

+  From  experiments  made  on  the  tensile  strength  of  isolated  filaments  of  ramie, 
it  appears  that  this  fibre  has  a  breaking  strain  of  from  17  to  18  grams.  Ramie 
degummed  in  the  laboratory  of  Fremy  showed  a  breaking  strain  of  from  21  to  22 
grams,  and  by  very  careful  degumming  it  has  been  possible  to  attain  a  strength 
of  from  35  to  40  grams.  Isolated  fibres  of  hemp  show  a  breaking  strain  of  only 
5  grams. 


412 


THE  TEXTILE   FIBRES 


the  least  affected  by  moisture.  It  has  three  times  the  strength 
of  hemp,  and  the  fibres  can  be  separated  to  almost  the  fineness 
of  silk.  The  fibre  is  exceptionally  white  in  color,  being  almost 
comparable  to  bleached  cotton  in  this  respect,  and  does  not 
appear  to  have  any  natural  coloring  matter  at  all.  It  also  has 
a  high  lustre,  excelling  linen  in  this  respect.* 

The  following  table  gives  the  chief  physical  factors  of  the 
ramie  fibre  in  comparison  with  the  other  principal  fibres: 


Ramie. 

Hemp. 

Flax. 

Silk. 

Cotton. 

Tensile  Strength  
Elasticity 

IOO 
IOO 

36 

7^ 

25 
66 

13 

4.OO 

12 
IOO 

Torsion 

IOO 

QIT 

80 

600 

4.OO 

t  * 

Having  such  excellent  qualities  as  a  fibre,  it  would  be  natural 
that  ramie  should  have  had  considerable  attention  bestowed 
upon  it.  The  chief  difficulty  in  the  way  of  its  universal  and 
wide-spread  adoption  has  been  the  lack  of  an  efficient  process 
for  properly  decorticating  the  fibre  from  the  rest  of  the  plant. 
In  China  and  India,  where  this  fibre  has  long  been  employed 
for  the  weaving  of  the  finest  and  most  beautiful  fabrics,  f  the 
decortication  of  the  fibre  is  carried  out  by  hand.  This,  of  course, 
would  be  impracticable  in  western  countries. 

On  French  authority  it  is  stated  that  the  yield  of  decorticated 
fibre  from  the  green,  unstripped  stalks  amounts  to  about  2  per 
cent,  and  of  degummed  fibre  about  i  per  cent.  Based  on  the 
weight  of  dry,  stripped  stalks,  the  yield  of  the  degummed  fibre 
would  be  about  10  per  cent. 

The  bast  of  the  ramie  cannot  be  removed  from  the  woody 
tissue  in  which  it  is  imbedded  by  a  simple  retting,  as  in  the  case 
of  flax  and  other  bast  fibres.  It  must  undergo  a  severe 

*  Cottonized  ramie  is  fibre  on  which  the  degumming  process  has  been  carried 
too  far,  with  the  result  that  the  individual  filaments  have  been  more  or  less  sepa- 
rated into  their  elements;  the  fibre  is  white,  but  without  the  characteristic 
transparency  and  lustre  of  ordinary  ramie. 

f  The  brilliant  and  transparent  fabrics  known  in  China  as  A-pou  and  sold 
in  England  under  the  name  of  grass  doth  are  made  from  ramie. 


JUTE,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE  FIBRES     413 

mechanical  treatment,  whereby  the  outer  bark  is  removed. 
The  long,  fibrous  tissue  so  obtained  consists  of  the  ramie 
filaments  held  together  in  the  form  of  a  ribbon  by  a  large  quan- 
tity of  gum,  and  before  the  fibres  can  be  combed  out  this  gum 
must  be  removed  by  chemical  treatment.  The  gummy  matters 
seem  to  consist  essentially  of  pectose,  cutose,  and  vasculose. 
In  the  degumming,  the  object  is  to  remove  these  substances 
without  affecting  the  cellulose  of  the  fibre  proper.  The  vasculose 


FIG.  93. — Ramie  Fibre.  (X34O.)  v,  swollen  displacements;  r,  fissures;  e,  point 
or  end;  q,  cross-sections;  i,  inner  layers  of  fibre- wall;  /,  lumen;  sch,  strati- 
fications. (Hohnel.) 


and  cutose  may  be  dissolved  by  treatment  with  soap  or  caustic 
alkalies  employed  under  pressure.  The  adhering  pectose  can 
then  be  detached  mechanically  by  washing. 

Though  ramie  has  many  excellent  qualities  to  recommend  it 
as  a  textile  fibre  for  definite  uses,  nevertheless  it  lacks  the  elas- 
ticity of  wool  and  silk  and  the  flexibility  of  cotton.  As  a  result 
it  yields  a  harsher  fabric,  which  has  not  the  softness  of  cotton. 
Owing  to  its  smooth  and  regular  surface,  it  is  difficult  to  spin 


414 


THE  TEXTILE  FIBRES 


to  fine  counts,  as  the  fibres  lack  cohesion  and  will  not  adhere 
to  each  other. 

Microscopically  the  ramie  .fibre  *s  remarkable  for  the  large 
size  of  its  bast-cells.  These  are  from  60  to  250  mm.  in  length 
and  up  to  80  pi  in  width.  The  diameter  of  the  fibre  is  also  charac- 
teristically uneven,  sometimes  narrow  with  heavy  cell- walls  and 
well-defined  lumen  and  at  other  times  broad  and  flat  with  an 


FIG.  94.— Ramie  Fibre.  (X35°0  A  lumen;  '  G,  granular  matter  in  lumen; 
S,  long  shreds  of  matter  in  lumen;  K,  knots  in  fibre.  (Micrograph  by 
author.) 


indistinct  lumen,  but  showing  heavy  striations  along  the  fibre. 
The  ratio  of  the  length  of  the  fibre  to  its  breadth  is  about 
i :  2400.  The  fibre  consists  of  pure  cellulose  with  no  indication 
of  the  presence  of  any  lignin  as  iodin  and  sulphuric  acid  give  a 
pure  blue  stain,  and  anilin  sulphate  gives  no  color.  In  an  ammo- 
niacal  solution  of  copper  oxide  ramie  becomes  greatly  swollen, 
but  does  not  dissolve.  The  ramie  fibre  gives  a  blue  coloration 


JUTE,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE  FIBRES     415 

with  the  chlor-iodide  of  zinc  reagent,  and  rose-red  with  chlor- 
iodide  of  calcium;  white  ramie  gives  no  coloration  with  anilin 
sulphate,  but  green  ramie  gives  a  slight  yellow  color,  which  seems 
to  indicate  a  slight  degree  of  lignification  in  the  case  of  the  latter 
fibre.  Along  the  fibre,  joints  and  transverse  fissures  are  of 


FIG.  95. — Cross-section  of  Ramie  Straw.  Showing  transverse  section  of  bast 
region  only;  the  bast-fibres  are  to  be  distinguished  by  their  large  area  from 
the  adjacent  tissue.  (Cross  and  Bevaii.) 


frequent  occurrence  (see  Fig.  94).  The  lumen  is  especially 
broad  and  easily  noticeable.  The  ends  of  the  fibre  elements 
have  a  thick-walled,  rounded  point,  and  the  lumen  is  reduced  to  a 
line.  At  places  the  lumen  appears  to  be  more  or  less  filled  with 
granular  matter,  and  sometimes  with  long  uneven  shreds  of 


416 


THE   TEXTILE   FIBRES 


matter,  evidently  dried-up  albuminous  matter.  The  cross- 
section  of  the  fibre  (see  Fig.  92)  shows  usually  only  a  single 
element  or  a  group  of  but  a  few  members.  The  cross-section 
is  also  quite  large,  and  is  elliptical  in  shape;  the  lumen  appears 
open,  and  frequently  contains  granular  matter.  The  cross- 
section  also  frequently  shows  strong  evidence  of  stratification. 
The  fibres  are  frequently  very  broad,  and  at  these  parts  are 
flat  and  ribbon-like  in  form,  but  are  never  twisted  (see  Fig.  94). 
Miiller  gives  the  following  analysis  of  the  raw  fibre  of  samples 
of  both  China  grass  and  ramie : 


Constituent. 

China 
Grass. 

Ramie. 

Ash                             

2   87 

<C  6* 

Water  (hygroscopic) 

9oe 

IO    I  S 

Aqueous  extract  
Fat  and  wax 

6.47 

O    21 

10-34 
o  ^o 

Cellulose  

78    07 

66    22 

Intercellular  substances  and  pectin  .  . 

6.  10 

12.  70 

4.  Hemp  is  a  name  applied  to  a  large  number  of  bast  fibres 
more  or  less  analogous  in  appearance  and  properties. 

Among  the  different  varieties  of  hemp  appearing  in  trade 
may  be  enumerated  the  following  (Dodge) : 

Ambari  (or  brown)  hemp Hibiscus  cannabinus 

Bengal  (or  Bombay)  hemp Crotalaria  juncea 

Black-fellow's  hemp Commersonia  fraseri 

Bowstring  hemp  (Africa) Sansevieria  guineensis 

Bowstring  hemp  (Florida) 5.  longiflora 

Bowstring  hemp  (India) S.  roxburghiana 

Calcutta  hemp Jute 

Cebu  hemp Musa  textilis 

Colorado  River  hemp Sesbania  macrocarpa 

Cretan  hemp Datisca  cannabina 

Cuban  hemp Fourcroya  cubensis 

False  hemp  (American) Rhus  typhina 

False  sisal  hemp Agave  decipiens 

Giant  hemp  (China) Cannabis  gigantea 

Hayti  hemp Agave  fostida 

Ife  hemp Sansevieria  cylindrica 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     417 

Indian  hemp .  . Apocynum  cannabinum 

Jubbulpore  hemp  (Madras) Crotalaria  tenuijolia 

Manila  hemp M usa  textilis 

New  Zealand  hemp  (or  flax) Phormium  tenax 

Pangane  hemp Sansevieria  kirkii 

Pita  hemp Yucca  sp. 

Pua  hemp  (India) Maoutia  puya 

Queensland  hemp Sida  retusa 

Rangoon  hemp Laportea  gigas 

Roselle  hemp Hibiscus  sabdariffa 

Sisal  hemp Agave  rigida 

Sunn  hemp Crotalaria  juncea 

Swedish  hemp Urtica  dioica 

Tampico  hemp Agave  heteracantha 

Water  hemp Eupatorium  cannabinum 

Wild  hemp Maoutia  puya 

Hemp  proper,  or  the  so-called  common  hemp,  is  derived  from  the 
bast  of  Cannabis  saliva.  This  is  a  shrub*  growing  from  6  to 
15  feet  in  height,  and  though  originally  a  native  of  India  and 
Persia,  it  is  now  cultivated  in  nearly  all  the  temperate  and 
tropical  countries  of  the  world.  At  the  present  time  it  is  quite 
extensively  grown  in  America,  f  though  not  as  yet  in  sufficient 
amount  to  satisfy  the  home  consumption.  Russia  produces 
an  enormous  quantity  of  hemp;  in  fact,  this  fibre  forms  one 
staple  article  of  export  from  that  country.  Poland  is  also  a 
large  producer.  French  hemp,  though  not  grown  to  such  an 

*  The  hemp  is  an  annual  plant,  with  a  straight  stalk,  and  elongated,  highly 
dentated  leaves.  The  latter  have  a  narcotic  odor,  and  occur  in  bunches  of  three, 
five,  or  seven.  The  flower  is  without  petals  and  develops  into  the  well-known 
hemp-seed  on  maturity.  The  hemp  plant  is  dioecious;  that  is,  it  .belongs  to  the 
class  of  plants  in  which  the  sexes  are  divided,  some  stems  bearing  only  clusters  of 
male  flowers  (panicles),  while  others  bear  only  female  flowers  (catkins).  The 
female  plant  grows  from  6  to  8  feet  in  height,  while  the  male  plant  (fimble 
hemp}  is  shorter. 

f  Several  varieties  of  hemp  are  grown  in  this  country;  that  cultivated  in 
Kentucky  and  having  a  hollow  stem  being  most  common.  China  hemp  and 
Smyrna  hemp  are  also  grown,  and  in  California,  Japanese  hemp  is  cultivated 
and  gives  a  remarkably  fine  product.  Five  varieties  of  hemp  appear  to  be  culti- 
vated in  Europe :  the  common  hemp,  Bologne  hemp  (known  also  as  Piedmontese 
hemp  or  great  hemp),  Chinese  hemp,  small  hemp  (the  .Canapa  piccola  of  Italy), 
and  Arabian  hemp.  The  latter  is  also  known  as  Takrousi  and  is  chiefly  cultivated 
for  its  resinous  principle,  from  which  hasheesh  is  obtained. 


418 


THE  TEXTILE   FIBRES 


extent,  is  much  superior  in  quality  to  that  from  either  Russia 
or  Poland,  it  being  fine,  white,  and  lustrous.  Italian  hemp  is 
also  of  a  very  high  grade.  In  India  hemp  is  not  grown  so  much 
for  its  fibre  as  for  the  narcotic  products  obtained.  Japanese 
hemp  is  of  excellent  quality,  and  appears  in  trade  in  the  form 
of  very  thin  ribbons,  smooth  and  glossy,  of  a  light  straw  color, 
and  the  frayed  ends  showing  a  fibre  of  exceeding  fineness.  Hemp 
appears  to  have  been  the  oldest  textile  fibre  used  in  Japan. 

The  hemp  fibre  is  obtained  from  the  plant  by  a  process  of 
retting  similar  to  that  employed  for  flax  *  the  plant  being  passed 


FIG.  96. — Ramie  Fibre.     (X420.)     Showing  the  longitudinal  ridges  and  knot- 
like  cross-markings.     (Micrograph  by  author.) 

through  about  the  same  operations,  such  as  rippling,  retting, 
breaking,  and  heckling.  The  broken  hemp  is  known  as  bast 
hemp,  and  the  heckled  as  pure  hemp.  The  latter  is  separated 
into  shoemaker's  and  spinning  hemp.  The  tow  separated  in 
hackling  is  used  for  stuffing  in  upholstery.  The  method  of 
dew-retting  is  chiefly  used;  that  is,  the  stalks  are  spread  out 

*  The  plant  is  ready  for  pulling  when  the  lower  leaves  become  limp  and  the 
tip  of  the  stalk  turns  yellowish.  The  male  plants  are  pulled  first  and  the  female 
plants  about  2  to  3  weeks  later. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     419 

in  the  fields  until  the  action  of  the  elements  causes  the  woody 
tissue  and  gums  enclosing  the  fibres  to  decompose.  Retting  in 
pools  of  water  has  been  practised  to  a  slight  extent,  but  evidently 
not  with  much  success.*  It  is  said  that  100  parts  of  raw  hemp 
furnish  25  parts  of  raw  fibre  or  filasse;  and  100  parts  of  the  lat- 
ter yield  65  parts  of  combed  filasse  and  32  parts  of  tow.f 

Hemp  fibre,  prepared  by  water-retting  as  practised  in  Italy, 
is   of  a   creamy-white   color,   lustrous,   soft,   and   pliable.      It 


FIG.  97. — Hemp  Fibres.     (Xsoo.)     (Micrograph  by  author.) 

makes  a  satisfactory  substitute  for  flax,  and  is  used  for  medium 
grades  of  nearly  all  classes  of  goods  commonly  made  from  flax, 

*  Baden  hemp,  which  is  a  much-prized  variety,  is  prepared  by  stripping  the 
bast  from  the  retted  stalks  by  hand.  The  product  is  entirely  free  from  shives. 

f  The  commercial  fibre  is  pearly  gray,  yellowish  or  greenish  to  brown  in  color, 
and  from  40  to  80  inches  in  length.  Its  fineness  of  staple  is  less  than  that  of  linen, 
though  its  tensile  strength  is  appreciably  greater.  The  best  qualities  of  hemp  are 
very  light  in  color  and  possess  a  high  lustre  almost  equal  to  that  of  linen.  The 
annual  production  of  hemp  fibre  is  about  600,000,000  pounds. 


420 


THE  TEXTILE  FIBRES 


except  the  finer  linens.  When  prepared  by  dew-retting,  as 
practised  in  this  country,  the  fibre  is  gray,  and  somewhat  harsh 
to  the  touch.  It  is  used  for  yacht  cordage,  ropes,  fishing- 
lines,  linen  crash,  homespuns,  hemp  carpets,  and  as  warp 
in  making  all  kinds  of  carpets  and  rugs.* 

The  seed  of  the  hemp  plant,  like  that  from  flax,  is  also 
utilized  for  the  oil  it  con  tains  ;f  100  parts  of  seed  furnish  27 
parts  of  oil.  So  this  forms  an  extensive  and  important  by- 
product in  the  cultivation  of  hemp. 

Under  the  microscope  the  hemp  fibre  is  seen  to  consist  of 
cell  elements  which  are  unusually  long,  averaging  about  20  mm. 


FIG.  98. — Hemp  Fibres.    (Xsoo.)    b,  longitudinal  views;  c,  ends;  a,  cross-sections. 
(After  Cross  and  Bevan.) 

in  length,  but  varying  from  5  to  55  mm.  The  diameter,  how- 
ever, is  very  small,  averaging  22  pi,  and  varying  from  16  to  50  [JL. 
Hence  the  ratio  between  the  length  and  diameter  is  about 
1000.  The  fibre  is  rather  uneven  in  its  diameter,  and  has 
occasional  attachments  of  fragmentary  parenchymous  tissue. 

*  Yearbook,  Dept.  Agric.,  1903. 

f  Hemp  seed  yields  a  greenish-colored  oil  having  a  peculiar  odor.  It  is  used 
in  the  making  of  green  soap  for  the  preparation  of  artist's  colors  and  varnishes, 
and  in  some  localities  for  the  making  of  oil-gas.  Hemp  seed  is  also  used  as  a 
bird  food,  and  in  some  countries  (Russia)  is  an  article  of  diet. 


JUTE,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE  FIBRES     421 

In  its  linear  structure  the  fibre  exhibits  frequent  joints,  longi- 
tudinal fractures,  and  swollen  fissures.  The  lumen  is  usually 
broad,  but  toward  the  end  of  the  fibre  it  becomes  like  a  line 
(see  Fig.  102).  It  shows  scarcely  any  contents.  The  ends  of 
the  filaments  are  blunt  and  very  thick-walled,  and  often  possess 
lateral  branches.*  The  cross-section  generally  shows  a  group 
of  cells  which  nearly  always  have  rounded  edges  and  are  not  so 
sharp-angled  and  polygonal  as  in  the  case  of  jute.  There  is 
also  a  median  layer  between  the  cells,  which  is  evidenced  by 
it  turning  yellow  on  treatment  with  iodin  and  sulphuric  acid.f 
In  the  section  the  lumen  appears  irregular  and  flattened,  and 
does  not  show  any  contents.  The  cell-walls  frequently  exhibit 
a  remarkable  stratification,  the  different  layers  yielding  a  variety 
of  colors  on  treatment  with  iodin  and  sulphuric  acid. 

When  examined  under  polarized  light,  hemp  shows  very 
bright  colors  similar  to  linen  and  ramie.  Hemp  also  gives  the 
following  microchemical  reactions:  (a)  with  iodin-sulphuric 
acid  reagent,  bluish  green  coloration;  (b)  with  chlor-iodide  of 
zinc,  blue  or  violet,  with  traces  of  yellow;  (c)  chlor-iodide  of 
calcium,  rose  red  with  traces  of  yellow;  (d)  anilin  sulphate, 
yellowish  green  coloration;  (e)  ammoniacal  fuchsin  solution, 
pale-red  coloration;  (/)  with  Schweitzer's  reagent  the  hemp 
fibres  swell  irregularly  with  a  characteristic  appearance  (see 
Fig.  100)  and  after  a  while  dissolve  almost  completely,  leaving 
only  the  fragments  of  parenchymous  tissue. 

Hemp  is  "sometimes  difficult  to  distinguish  microscopically 
from  flax;  but  the  two  may  readily  be  told  by  an  examination 
of  the  ends  of  the  fibres,  hemp  nearly  always  exhibiting  specimens 

*  Forked  ends  are  very  characteristic  of  hemp  fibres,  but  such  a  condition 
is  never  observed  with  flax. 

t  The  intercellular  (median  layer)  matter  which  binds  the  elements  of  the 
hemp  together  contains  vasculose,  and  even  the  cellulose  of  the  fibre  itself  appears 
to  be  impregnated  with  this  substance.  This  is  the  cause  of  the  stratified  appear- 
ance of  the  cell-wall  when  the  fibre  is  treated  with  the  iodin-sulphuric  acid  reagent. 
When  the  hemp  fibre  is  viewed  longitudinally  and  is  treated  with  the  above  reagent, 
a  green  color  is  obtained,  due  to  the  mixing  of  the  yellow  of  the  vasculose  layer 
and  the  blue  of  the  cellulose  layer.  By  this  means  hemp  may  readily  be  dis- 
tinguished from  linen,  which  gives  a  characteristic  blue  color. 


422 


THE  TEXTILE  FIBRES 


of  forked  ends,  whereas  flax  never  has  this  peculiarity.  The 
fibres  of  hemp  are  also  less  transparent  than  those  of  linen,  and 
the  interior  canal  is  often  more  difficult  to  distinguish,  on  account 
of  the  numerous  striations  on  the  surface.  The  difference  in 
the  appearance  of  the  cross-sections  is  also  of  service  in  dis- 
criminating between  these  two  fibres.  Again,  the  parenchymous 
tissue  which  frequently  occurs  as  attached  fragments  to  hemp 
fibres  is  rich  in  star-shaped  crystals  of  calcium  pxalate,  and  this 
is  scarcely  ever  to  be  noticed  in  the  case  of  flax.  A  peculiarity 


FIG.  99. — Part  of  Cross-section  of  Hemp  Stalk.     (X200.)     B,  woody  tissue;  / 
secondary  layer  of  fibres;  F,  main  layer  of  fibres.     (After  Le  Comte.) 


to  be  noticed  in  the  examination  of  hemp  is  the  occasional 
presence  of  long  narrow  cells  filled  with  reddish-brown  matter, 
insoluble  in  the  ordinary  solvents.  These  cells  occur  between 
the  fibres  as  well  as  in  the  bast,  and  probably  contain  tannin. 
They  are  not  to  be  found  in  flax.  The  behavior  of  isolated 
hemp  cells  with  ammoniacal  copper  oxide  solution  is  also  quite 
characteristic;  the  cell  membrane  acquires  a  blue  to  a  bluish 
green  color,  and  swells  up  like  a  blister,  showing  sharply  defined 
longitudinal  striations.  The  inner  cell-wall  remains  intact 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     423 


in  the  form  of  a  spirally  wound  tube  contained  inside  the  strongly 
swollen  mass  of  the  fibre. 

The  hemp  fibre  is  not  composed  entirely  of  pure  cellulose, 
as  it  gives  a  yellow  to  yellowish  green  coloration  with  anilin 
sulphate,  and  a  greenish  color  with  iodin  and  sulphuric  acid. 
Both  hydrochloric  acid  and  caustic  potash  give  a  brown  colora- 
tion, while  ammonia  produces  a  faint  violet.  It  appears  to  be 
a  mixture  of  cellulose  and  bastose.  Bleached  hemp,  however, 

B 


FIG.  100. — Hemp  Fibres  Treated  with  Schweitzer's  Reagent.  ( Xsoo.)  A ,  strongly 
lignified  fibre;  B,  fibre  free  from  ligneous  matter;  i,  i,  skin  of  inner  canal; 
a,  external  ligneous  tissue;  s,  swollen  cellulose.  (After  Wiesner.) 

shows  the  reactions  of  pure  cellulose.     Miiller  gives  the  follow- 
ing analysis  of  a  sample  of  the  best  Italian  hemp: 

Per  Cent. 

Ash 0.82 

Water  (hygroscopic) 8 . 88 

Aqueous  extract 3-48 

Fat  and  wax 0.56 

Cellulose 77-77 

Intercellular  matter  and  pectin  bodies 9.31 


424  THE  TEXTILE  FIBRES 

Hemp  appears  to  contain  more  hygroscopic  moisture  than 
cotton  or  linen.  Samples  examined  by  the  author  contained 
8  per  cent  moisture  compared  with  6  per  cent  for  cotton  under 
the  same  conditions.  At  the  Roubaix  conditioning  house  the 
regain  allowed  on  hemp  is  12  per  cent,  and  this  same  figure 
was  fixed  by  the  International  Congress  at  Turin. 

Hemp  is  principally  employed  for  the  manufacture  of  twine 
and  cordage,  for  which  its  great  strength  eminently  adapts  it; 
and,  besides,  it  is  a  very  durable  fibre,  and  is  not  rotted  by  water. 


FIG.  101. — Fibres  of  Hemp.     (X3oo.)     Showing  longitudinal  fissures  and  trans- 
verse cracks  and  jointed-like  structure.     (Micrograph  by  author.) 


In  this  respect  it  differs  very  essentially  from  jute.  Ordinary 
hemp  is  seldom  used,  however,  for  woven  textiles,  as  it  is  harsh 
and  stiff,  and  not  sufficiently  pliable  and  elastic.  It  also  pos- 
sesses a  rather  dark-brown  color,  and  cannot  be  successfully 
bleached  without  serious  injury  to  the  quality  of  the  fibre. 

Cuban  hemp  of  trade  is  the  fibre  from  Fourcroya  cubensis, 
a  plant  native  to  tropical  America,  and  having  long  leaves  in 
which  the  fibre  is  found.  The  fibre  is  of  very  good  quality  and 
is  similar  to  sisal  hemp.  Another  species,  the  F.  gigantea, 
or  giant  lily,  also  gives  a  good  fibre  which  closely  resembles 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     425 

sisal  hemp  and  no  doubt  is  often  sold  in  trade  for  this  latter  fibre. 
It  is  also  grown  in  tropical  America,  and  the  fibre  is  called 
by  the  natives  fique,  and  is  principally  employed  for  the  mak- 
ing of  bagging,  horse  blankets,  etc.  It  is  known  in  Venezuela 
as  cocuiza. 

5.  Sunn  Hemp  is  the  bast  fibre  of    the  Crotalaria  juncea; 


FIG.  102. — Hemp  Fibres.     (Xaoo.)     L,  lumen;    /,  joint-like  structure. 
(Micrograph  by  author.) 


it  is  also  known  by  the  names  of  Conkanee,  Indian,*  Brown, 
and  Madras  hemp.     It  grows  abundantly  in  the  countries  of 

*  True  Indian  hemp  is  the  bast  fibre  from  Apocynum  cannabinum;  this  fibre 
is  a  light  cinnamon  in  color  and  is  long  and  tenacious.  It  was  principally  employed 
by  the  North  American  Indians  who  made  bags,  mats,  belts,  and  cordage  from 
it.  Spon  mentions  Indian  hemp  under  the  common  name  of  "  Colorado  hemp," 
but  this  latter  name  really  belongs  to  the  fibre  from  Sesbania  macrocarpa.  To 
the  same  family  (Papilionacece)  as  sunn  hemp  belong  two  other  species  of  plants 
which  yield  valuable  fibres  for  paper  manufacture,  namely  Spanish  broom  (spar- 
tium  junceum)  and  German  broom  (Spartium  scoparium). 


426 


THE  TEXTILE  FIBRES 


southern  Asia,  and  is  largely  used  in  the  manufacture  of  cordage. 
It  appears  to  have  been  one  of  the  earliest  fibres  mentioned  in 
Sanscrit  literature.*  The  fibre  is  obtained  from  the  plant  by  a 
system  of  retting  very  similar  to  that  of  flax.  The  fibre  of  sunn 
hemp  is  of  a  better  quality  than  jute,  being  lighter  in  color, 
of  a  better  tensile  strength,  and  more  durable  to  exposure,  f 


*  It  was  known  in  the  Institutes  of  Manu  under  the  name  of  sana.  This 
hemp  was  also  probably  known  to  the  Chinese  at  a  very  remote  date. 

t  The  following  tables  of  comparative  tensile  strengths  for  various  cordage 
fibres  have  been  adopted  from  Royle's  work  on  The  Fibrous  Plants  of  India;  the 
tests  were  made  on  ropes  of  the  same  size  and  1.2  metres  in  length. 

I.  COMPARATIVE  STRENGTH,  DRY  AND  WET 


Fibre. 

Dry,  Kilos. 

Wet,  Kilos. 

Hemp  from  Calcutta  

72 

86 

Sunn  hemp  (fresh  retted) 

ci 

72 

'  '          (retted  after  drying)  

27 

sc 

Jute  (Corchorus  capsularis)  

65 

66 

'  '     (C.  olitorius} 

crj 

^6 

'  '     (C.  str  ictus]  

47 

C2 

Gambo  hemp  (Hibiscus  cannabinus)  
Roselle  hemp  (H.  sabdariffa)  

52 
41 

60 
C2 

Hibiscus  abelmoschus  

40 

40 

Ramie  (Bcehmeria  tenacissima). 

no 

126 

II.  COMPARATIVE   STRENGTH   OF   PREPARED  ROPES,  AND  AFTER  STEEPING   TN 

WATER  116  DA\S 


Fibre. 

Prepared  Ropes. 

Water- 
soaked. 

Natural. 

Natural. 

Tanned. 

Tarred. 

Hemp,  English 

47 
34 
39 
3i 
3i 
17 
50 
54 

63 

31 
31 

36 
33 

20 

27 
28 

35 

22 

Rotted 

24 
Rotted 
18 

Rotted 

« 

13 

'  '       Calcutta 

Coir  

Sunn  hemp  

Tute 

Linen,  Calcutta  

Agave  americana      

Sansevieria  zeylanica 

JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     427 


Dr.  Wright  gives  the  following  table  for  the  strength  of  several 
cordage  fibres:* 

Pounds. 

Sunn  hemp 407 

Cotton  rope .- 346 

Hemp 290       * 

Coir 224 


FIG.  103. — Sunn  Hemp.  (X325.)  L,  view  of  middle  portion;  v,  joints;  I, 
lumen;  s,  pointed  ends;  q,  cross-sections;  m,  outer  layer  of  fibre;  «,  inner 
layers.  (Hohnel.) 

In  appearance  sunn  hemp  is  very  similar  to  hemp,  both  to 
the  naked  eye  and  under  the  microscope.  The  raw  fibre  is 
coarse,  flattened,  and  dark  gray  in  color;  the  purified  fibre  is 
yellowish  gray,  rather  lustrous,  and  of  a  fine  texture. 

The  essential  distinction  between  sunn  hemp  and  hemp 
is  in  the  cross-section  of  the  former  (see  Fig.  103),  which  shows 

*  According  to  Roxburgh,  similar  lines  of  jute  and  sunn  hemp  showed  the 
following  comparative  tensile  strengths: 


Dry. 

Wet. 

Tute 

14? 

146 

Sunn  hemp                      

1  60 

2OO 

428  THE  TEXTILE  FIBRE8 

the  presence  of  a  very  thick  median  layer  of  lignin  between  the 
individual  cells.  The  lumen  in  the  cross-section  is  also  usually 
rather  thick,  and  often  contains  yellowish  matter  differing 
in  these  respects  from  hemp,  in  which  the  lumen  is  flat  and  narrow 
and  always  empty.*  The  bast-cells  of  sunn  hemp  are  13-50  ^ 
broad,  and  in  longitudinal  view  are  partly  striated,  and  also 


FIG.  104. — Leaf  and  Blossom  of  Crotalaria  juncea. 
(After  Bulletin  U.  S.  Dept.  Agric.) 

show  dislocations  and  cross-marks.     The  ends  are  thickened 
and  either  blunt  or  narrowed  with  warty  irregularities.     lodin 

*  Another  variety  of  Crotalaria  used  for  its  fibre  is  the  C.  tenuifolia  from 
which  is  obtained  the  Jubbulpore  hemp.  This  fibre  is  said  by  some  to  be  superior 
to  that  of  Russian  hemp  (Cannabis  saliva],  its  relative  tensile  strength  being  c;5 
pounds  to  80  pounds  for  the  latter.  The  fibre  is  4  to  5  feet  in  length,  and  resem- 
bles the  best  St.  Petersburg  hemp.  The  fibre  C.  retusa^  is  also  to  be  found  in 
India  under  the  name  of  sunn  hemp;  C.  sericea  and  C.  striata  are  other  species 
which  are  also  employed  for  fibre. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     429 


and  strong  sulphuric  acid  produce  a  peculiar  swelling  of  the 
fibre,  the  outer  yellow  layer  becoming  converted  into  a  yellow 
mass  over  which  flows  the  blue  semi-liquid  mass  of  cellulose, 
leaving  as  a  residue  a  greenish  yellow  inner  tube.  With  iodin 
and  sulphuric  acid  sunn  hemp  gives  a  greenish  blue  coloration, 
and  with  chlor-iodide  of  zinc  brownish  blue.  This  would 
indicate  that  the  fibre  is  of  rather  pure  cellulose,  but  enveloped 
with  a  layer  of  lignified  tissue. 

Miiller  gives  the  following  analysis  of  raw  sunn  hemp: 

Per  Cent. 

Ash 0 .  6l 

Water  (hygroscopic)  * 9 . 60 

Aqueous  extract 2.82 

Fat  and  wax o .  55 

Cellulose 80 . 01 

Pectin  bodies 6.41 

6.  Ambari  or  Gambo  Hemp  is  an  East  Indian  fibre  derived 
from  the  bast  of  Hibiscus  cannabinus.^  The  fibre  when  care- 

*  According  to  Wiesner  sunn  hemp  contains  a  lower  percentage  of  moisture 
than  any  other  vegetable  fibre.  He  gives  the  amount  for  air-dried  fibre  as  5.34 
per  cent,  and  after  exposure  to  an  atmosphere  saturated  with  steam  as  10.87 
per  cent.  It  is  probable,  however,  that  after  being  stored  for  some  time  the  fibre 
of  sunn  hemp  will  show  a  higher  percentage  of  moisture. 

f  Another  variety  of  Hibiscus  which  is  sometimes  used  as  a  fibre  plant  is  the 
H.  escidentus,  or  common  okra.  The  bast  of  this  plant  at  one  time  attracted 
considerable  attention  in  the  Southern  States  as  a  possible  substitute  for  jute  in 
the  manufacture  of  bagging  for  cotton.  The  fibre  is  said  to  be  as  white  as  New 
Zealand  flax,  considerably  lighter  than  jute,  but  more  brittle  and  not  so  strong. 
The  filaments,  however,  are  smooth  and  lustrous  and  quite  regular.  It  is  used 
somewhat  in  India  for  the  manufacture  of  twine  and  cordage,  and  as  an  adul- 
terant for  jute.  According  to  the  tests  of  Dr.  Roxburgh,  the  fibre  of  Indian  okra 
gave  the  following  results  compared  with  hemp  and  jute: 


Breaking  Strain,  Pounds. 

Dry. 

Wet. 

Indian  okra  .    . 

79 
"3 
158 
"5 
95 
104 
89 

95 
125 
190 

133 
117 

H5 
92 

Jute.  . 

Hemp  (Bengal)  . 

Hibiscus  cannabinus. 

H.  sabdarifla 

H,  str  ictus 

H.furcatus  

The  bast  fibre  of  H.  tiliaceus  (the  majagua)  has  some  interest  in  the  fact  that, 


430  THE  TEXTILE  FIBRES 

fully  prepared  is  from  5  to  6  feet  in  length;  it  is  of  a  lighter 
color  than  hemp,  and  harsher.  Its  tensile  strength  is  some- 
what less  than  that  of  sunn  hemp.  Like  the  latter  fibre,  it  is 
principally  used  for  cordage,  though  it  is  also  employed  in 
India  for  the  manufacture  of  a  coarse  canvas.*  In  its  microscopic 
characteristics  ambari  hemp  is  very  similar  to  jute;  the  length 
of  the  fibre  elements  varies  from  2  to  6  mm.  and  the  diameter 
from  14  to  33  {A.  The  median  layers  of  lignin  between  the  cells 
are  broad,  and  are  colored  much  darker  than  the  inner  layers 
of  the  cell- wall  when  treated  with  iodin  and  sulphuric  acid. 
The  lumen  presents  the  same  appearance  as  with  jute  (see  Fig. 
105),  having  such  very  marked  contractions  that  in  places  it  is 
discontinuous.  The  ends  of  the  fibres  are  very  blunt  and  thick- 
walled. 

7.  New  Zealand  Flax  differs  somewhat  from  the  preceding 
fibres  in  that  it  is  derived  not  from  the  bast,  but  from  the  leaves 
of  the  flax  lily,  Phormium  tenax.  Botanically  these  are  known 
as  sclerenchymous  fibres.  Apart,  however,  from  this  histological 

according  to  the  experiments  of  Dr.  Roxburgh,  it  does  not  rot  when  immersed 
in  water  for  a  long  period,  as  most  other  fibres  do.  His  results  were  as  follows: 
A  cord  of  this  fibre  when  white  had  a  breaking  strain  of  41  Ibs.,  when  tanned 
62  Ibs.,  and  when  tarred  61  Ibs.;  a  similar  cord  when  macerated  in  water  for 
116  days,  when  white  broke  with  40  Ibs.,  when  tanned  55  Ibs.,  and  when  tarred 
70  Ibs.  English  hemp  and  Indian  hemp  when  treated  in  the  same  manner  were 
found  to  be  rotten,  and  sunn  hemp  broke  with  65  Ibs.,  and  jute  with  60  Ibs. 

*  The  fibre  is  said  to  be  white,  soft,  and  silky,  and  some  claim  it  to  be  more 
durable  than  jute  for  the  manufacture  of  coarse  textiles.  In  the  opinion  of  the 
author,  however,  these  qualities  of  this  fibre  have  been  somewhat  overestimated, 
as  it  is  not  as  white  and  soft  as  such  descriptions  would  lead  us  to  expect.  Accord- 
ing to  Dodge,  the  fibres  of  ambari  hemp,  as  compared  with  those  of  ordinary 
hemp,  are  of  a  paler  brown  color,  are  harsher,  and  adhere  more  closely  together, 
though  the  separate  fibres  are  further  divisible  into  fine  fibrils  which  possess  con- 
siderable strength.  According  to  Watt,  the  fibres  of  ambari  hemp  are  largely 
employed  by  the  natives  of  India  for  the  manufacture  of  ropes,  strings,  and  sacks 
which  are  principally  used  among  the  agricultural  districts.  "  The  length  of  the 
extracted  fibre  varies  between  5  and  10  feet;  the  fibre  is  somewhat  stiff  and  brittle, 
and  though  used  as  a  substitute  for  hemp  and  jute  is  inferior  to  both.  The  break- 
ing strain  has  been  variously  estimated  at  115  to  190  pounds.  The  fibre  is  bright 
and  glossy,  but  coarse  and  harsh.  Samples  of  the  fibre  exposed  for  two  hours  to 
steam  at  2  atmospheres,  followed  by  boiling  in  water  for  three  hours,  and  again 
steamed  for  four  hours,  lost  only  3.63  per  cent  by  weight  as  against  flax  3.50; 
Manila  hemp  6.07;  hemp  6.18  to  8.44;  and  jute  21.39  Per  cent." 


.H   IK,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     431 

difference,  such  fibres  are  very  similar  in  general  structure  to 
ordinary  bast  fibres.  Phormium  tenax  is  a  native  of  New 
Zealand,  but  is  also  found  distributed  in  other  portions  of  Austra- 
lasia such  as  Norfolk  Island;  it  has  been  introduced  into  several 
European  countries,  and  is  also  cultivated  to  quite  an  extent 


FIG.  105. — Gambo  Hemp.  (X325.)  e.  ends  with  blunt  points  and  wide  lumen; 
d,  lateral  branch;  /,  longitudinal  cutting  with  v,  interruptions  in  lumen;  q, 
cross-sections,  with  L,  small  lumen;  m,  median  layers.  (Hohnel.) 


in  California.     The  fibre  of  New  Zealand  flax  is  very  white 
in  color,  is  soft  and  flexible,  and  possesses  a  high  lustre.*     In 

*  The  fibre  is  40  to  60  inches  long,  nearly  white,  fine,  and  rather  soft  for  a  leaf 
fibre.  It  is  us;d  as  a  substitute  for  sisal  in  binder  twine,  baling  rope,  and  medium 
grades  of  cordage,  and  is  made  up  largely  in  mixtures  with  Manila  or  sisal,  except 
in  the  cheaper  tying  twines.  By  extra  care  in  preparation  and  hackling,  a  quality 
is  produced  almost  as  fine  and  soft  as  the  better  grades  of  flax,  and  when  thus 
prepared  it  may  be  spun  and  woven  into  goods  closely  resembling  linen.  (Year- 
book, Dept.  Agric.,  1903.) 


432 


THE  TEXTILE  FIBRES 


tenacity  it  appears  to  be  superior  to  either  flax  or  hemp,  as  is 
seen  by  the  following  comparative  figures  (Royle).* 

Pounds. 

New  Zealand  flax 23 . 70 

Flax 11.75 

Hemp 16 . 75 

/     .  P  f      f. 


FIG.  106. — New  Zealand  Flax.  /,  sclerenchymous  bundles;  p,  parenchymous 
matter;  /',  vascular  fibres;  e,  fibre  ends;  p',  porous  elements  of  vascular 
bundles;  g,  cross-section  of  bast  fibres;  /,  cross-section  of  vascular  bundles; 
Q,  cross-section  of  bast  fibre  bundle  with  accompanying  elements;  ep,  epi- 
dermis; c,  cuticle;  F,  bundle  proper;  p,  parenchyma.  (After  Hanausek.) 

*  Royle  also  furnishes  the  following  figures  for  the  breaking  strain  of  similar 
ropes  made  from  various  fibres: 

Fibre.  Breakin^Strain, 

Coir 102 

Gambo  hemp 133 

Sansevieria  zeylanica 144 

Cotton 157 

Pita 164 

Sunn  hemp 185 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     433 

The  leaves  of  Phormium  tenax  reach  over  5  feet  in  length, 
and  the  fibre  is  separated  by  first  scraping  the  leaves  and  then 
combing  out  the  separate  fibres.  No  process  of  retting  is  neces- 
sary, as  with  the  bast  fibres.*  The  method  of  preparing  the 
fibre,  however,  is  as  yet  very  unsatisfactory,  and  could  be  much 
improved.  The  amount  of  fibre  obtained  under  the  present 
method  of  operating  is  from  10  to  14  per  cent  on  the  weight  of 
the  leaves,  although  the  latter  contain  as  much  as  20  per  cent 
of  fibre. 


FIG.  107. — New  Zealand  Flax.     (Xsoo.)     (Micrograph  by  author.) 

In  their  microscopical  characteristics  the  fibres  of  New 
Zealand  flax  are  remarkable  for  their  slight  adherence.  The 
fibre  elements  are  from  5  to  15  mm.  in  length  and  from  10  to 
20  ^JL  in  diameter,  and  the  ratio  of  the  length  to  the  breadth  is 
about  550.  They  are  very  regular  and  uniformly  thickened, 
and  the  surface  is  smooth,  though  occasionally  exhibiting  wave 
like  irregularities  in  the  cell-wall  (see  Fig.  107).  The  lumen  is 

*  The  bundles  of  fibres  form  filaments  of  unequal  size,  which  are  easily  sepa- 
rated by  friction.  The  fibre  has  considerable  elasticity,  but  readily  cuts  with  the 
nail  (Dodge). 


434  THE  TEXTILE  FIBRES 

very  apparent,,  but  is  generally  narrower  than  the  cell- wall 
and  is  very  uniform  in  its  width.  The  ends  are  sharply  pointed 
and  not  divided.  The  cross-section  shows  rather  loosely 
adhering  elements  and  is  very  round  in  contour,  the  lumen 
being  either  round  or  oval,  and  is  empty.  Fragments  of  paren- 
chyma and  epidermis  are  frequently  to  be  noticed  on  the  fibres. 
No  median  layer, of  lignin  is  apparent  between  the  elements, 
though  the  fibres  themselves  are  completely  lignified.  With 
iodin  and  sulphuric  acid  the  fibres  give  an  intense  yellow 
coloration,  with  anilin  sulphate  a  pale  yellow,  with  chlor-iodide 
of  zinc  a  yellowish  brown,  with  ammoniacal  solution  of  fuchsin 
a  red;  with  Schweitzer's  reagent  the  fibres  are  rapidly  separated 
into  their  elements,  but  do  not  dissolve.  The  purified  fibre  of 
New  Zealand  flax  is  rather  difficult  to  distinguish  microscopically 
from  aloe  hemp  or  from  Sansevieria  fibre,  except  by  the  rounded 
and  separated  cross-sections.  The  fibre  also  usually  contains 
a  substance  derived  from  the  sap  of  the  leaf,  which  possesses  the 
peculiarity  of  giving  a  deep  red  color  with  concentrated  nitric 
acid.  The  composition  of  the  fibre  is  as  follows  (Church) : 

Per  Cent. 
Ash 0 .  63 

Water 11.61 

Gum  (and  other  matter  soluble  in  water) 21 .99 

Fat i .  08 

Pectin  bodies i  .69 

Cellulose 63 .  oo 

New  Zealand  flax  is  principally  employed  in  the  making  of 
cordage  and  twine  and  floor-matting,  though  the  best  fibre  can 
also  be  woven  into  cloth  resembling  linen  duck.  It  has  been 
•used  extensively  in  the  United  States  for  the  making  of  "  staff," 
being  mixed  with  plaster  for  this  purpose.*  The  chief  drawback 
to  the  fibre  of  New  Zealand  flax  is  its  poor  resistance  to  water,  f 

*  This  material  is  extensively  employed  for  the  building  of  temporary  struc- 
tures. It  was  used  on-  most  of  the  structures  of  the  Columbian  Exposition  at 
Chicago. 

f  Marine  Fibre  is  a  recent  product  obtained  by  dredging  in  the  shallow  water 
of  a  gulf  in  South  Australia.  Chemically  it  is  a  hydrated  lignocellulose,  giving 
the  typical  reactions  of  lignin.  Microscopically  it  is  very  similar  to  New  Zealand 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     435 

8.  Manila  Hemp  is  the  fibre  obtained  from  the  leaf-stalks 
of  the  Musa  textilis,  a  variety  of  plantain  which  is  a  native  of 
the  Philippine  Islands.*  The  plant  is  cut  down,  stripped  of 
its  leaves  and  then  sliced  into  narrow  longitudinal  strips  which 
are  scraped  while  still  fresh  until  the  fibres  are  exposed.  After 
drying  the  fibres  are  beaten  and  are  separated  into  three  grades: 
(i)  Bandala,  the  coarsest  and  strongest  fibres  from  the  outer 
portion  of  the  trunk;  (2)  Lupis  from  the  middle  layers;  and 
(3)  Tupoz,  the  finest  and  weakest  fibres  from  the  inner  part  of 
the  trunk.  A  single  plant  yields  about  one  pound  of  fibre. f 
The  fibre  is  white  and  lustrous  in  appearance,  light  and  stiff 
in  handle,  and  easily  separated.  It  is  also  a  very  strong  fibre, 
and  of  great  durability.  In  the  Philippines  it  is  known  as 
abaca. %  The  coarser  fibres  are  used  for  the  manufacture  of 
cordage,  for  which  purpose  it  is  eminently  suited  on  account 
of  its  great  strength.  §  The  light-colored  fibres  are  heckled  and 

flax.  From  this  it  is  to  be  concluded  that  the  fibre  is  not  of  marine  origin,  but 
has  been  produced  by  the  natural  retting  of  a  land  plant,  which  has  become 
submerged  by  the  sea.  Owing  to  its  lignified  character  it  dyes  directly  with 
basic  dyes  and  some  acid  dyes,  but  has  little  affinity  for  substantive  dyes.  The 
fibre  is  brittle  and  has  but  little  strength. 

*  The  commercial  supply  of  Manila  hemp  is  obtained  from  the  Philippine 
Islands;  "  cebu  hemp  "  is  a  trade  variety. 

f  Lupis  and  tupoz  serve  for  the  manufacture  of  fine  native  fabrics;  while 
bandala  is  used  for  a  coarse  fabric  known  as  Guimara,  and  more  especially  for 
cordage  (see  Semler,  Trap.  Agric.  vol.  3,  p.  712;  also  Schanz,  Die  Kultur  des 
Manilahanfes  anf  den  Philip pine'n;  Tropenpflanzen,  1904,  p.  116). 

i  The  abaca  plants  attain  a  height  of  8  to  20  feet,  the  trunk  being  composed 
chiefly  of  overlapping  leaf-sheaths.  When  the  flower-bud  appears,  the  entire 
plant  is  cut  off  close  to  the  ground.  The  leaf-sheaths,  5  to  1 2  feet  in  length,  are 
stripped  off,  separated  tangentially  into  layers  a  quarter  of  an  inch  or  less  in  thick- 
ness, and  these  in  turn  split  into  strips  i  to  2  inches  in  width.  While  yet  fresh 
and  green  these  strips  are  drawn  by  hand  under  a  knife  held  by  a  spring  against 
a  piece  of  wood.  This  scrapes  away  the  pulp,  leaving  .the  fibre  clean  and  white. 
After  drying  in  the  sun  the  fibre  is  tied  in  bunches  and  taken  to  the  principal 
towns  or  to  Manila  to  be  baled  for  export.  (Yearbook,  Dept.  Agric.,  1903.) 

§  The  best  grade  of  Manila  fibre  is  of  a  light  buff  color,  lustrous,  and  very 
strong,  in  fine,  even  strands  6  to  12  feet  in  length.  Poorer  grades  are  coarser 
and  duller  in  color,  some  of  them  yellow  or  even  dark  brown,  and  lacking  in 
strength.  The  better  grades  are  regarded  as  the  only  satisfactory  material  known 
in  commerce  for  making  hawsers,  ship's  cables,  and  other  marine  cordage  which 
may  be  exposed  to  salt  water,  or  for  well-drilling  cables,  hoisting  ropes,  and  trans- 
mission ropes  to  be  used  where  great  strength  and  flexibility  are  required.  The 


436 


THE  TEXTILE  FIBRES 


spun  into  yarns  for  coarse  weaving,  such  as  the  making  of 
market-bags,  etc.  The  finer  grades  are  also  used  sometimes 
for  the  making  of  coarse  upholstery  goods.  The  relative 
strengths  of  rope  made  from  English  hemp  and  that  made  from 
Manila  hemp  are  about  10  to  12  respectively.  The  finer  fibres 
which  require  to  be  selected  and  carefully  prepared,  are  woven 
into  a  very  high  grade  of  muslin,  which  brings  a  good  price 
even  in  Manila.*  Under  the  microscope  Manila  hemp  shows 
fibre  elements  of  3  to  12  mm.  in  length  and  16  to  32  ^  in  width, 
the  ratio  of  the  length  to  the  diameter  being  about  250.  The 


FIG.   108. — Manila  Hemp.     (Xsoo.)     a,  cross-sections;    b,  longitudinal  views; 
c,  ends.     (After  Cross  and  Bevan.) 

bundles  of  fibres  are  very  large,  but  by  treatment  with  an  alkaline 
bath  are  easily  separated  into  smooth,  even  fibres.  The  fibres 
are  very  uniform  in  diameter,  are  lustrous,  and  are  rather  thin- 
walled.  The  lumen  is  large  and  distinct,  but  otherwise  the 
fibre  does  not  exhibit  any  markings.  The  cross-sections  are 
irregularly  round  or  oval  in  shape,  and  the  lumen  in  the  section 
is  open  and  quite  large  and  distinct  (see  Fig.  108).  The  fibre 

best  grade  of  binder  twine  is  made  from  Manila  hemp,  since,  owing  to  its  greater 
strength,  it  can  be  made  up  at  650  feet  to  the  pound  as  compared  with  500  feet 
for  sisal.  (Yearbook,  Dept.  Agric.,  1903.) 

*  The  imports  of  Manila  hemp  into  the  United  States  during  1903  were  more 
than  500,000  bales  of  270  Ibs.  each.  During  the  past  ten  years  the  price  has 
ranged  from  4  to  14  cents  per  pound. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES    437 

bundles  frequently  show  a  series  of  peculiar,  thick,  strongly 
silicified  plates,  known  as  stegmata.  Lengthwise  these  appear 
quadrilateral  and  solid,  and  have  serrated  edges  and  a  round, 
bright  spot  in  the  centre.  The  stegmata  may  be  best  observed 
after  macerating  the  fibre  bundles  in  chromic  acid  solution; 
they  are  about  30  [L  in  length.  On  extracting  the  fibre  with 
nitric  acid,  then  igniting,  and  adding  dilute  acid  to  the  ash 
so  obtained,  the  stegmata  will  appear  in  the  form  of  a  string  of 
pearls,  frequently  in  long  chains  with  sausage-like  links,  a  very 


•    b 


FIG.  109. — Manila  Hemp.  (X325.)  q,  cross-sections;  /,  lumen  without  contents; 
J,  lumen  containing  granular  matter;  a,  silicious  skeleton  of  the  stegmata; 
6,  rows  of  stegmata,  flat  side;  c,  the  same,  narrow  side.  (Hohnel.) 

peculiar  and  characteristic  appearance.  The  lumen  often 
contains  a  yellowish  substance,  but  no  distinct  median  layer 
is  perceptible  between  the  fibres.  Manila  hemp  is  a  lignified 
fibre,  and  gives  a  yellow  color  with  anilin  sulphate;  iodin 
and  sulphuric  acid  give  a  golden  yellow  to  a  green  color;  caustic 
soda  colors  the  fibre  a  faint  yellow  and  causes  a  slight  disten- 
sion; ammoniacal  copper  oxide  causes  a  blue  coloration  and  a 
considerable  swelling.*  Manila  hemp  may  be  distinguished 

*  Besides  the  Musa  textilis,  the  fibre  from  the  following  varieties  is  also  utilized: 
Musa  paradisiaca,  M.  sapientium,  and  M.  mindanensis  from  India  and  islands 


438 


THE  TEXTILE   FIBRES 


from  sisal  by  the  color  of  the  ash,  that  of  the  former  being  of  a 
dark  gray  color,  whereas  sisal  leaves  a  white  ash.  According 
to  Miiller,  the  composition  of  Manila  hemp  is  as  follows: 


Per  Cent. 

1 .02 

-.. 11.85 

0.97 

0 . 63 

64.72 

Incrusting  and  pectin  matters 21 .83 


Ash 

Water 

Aqueous  extract . 
Fat  and  wax 
Cellulose .  . 


FIG.  no. — Manila  Hemp.     (X3oo.)     (Micrograph  by  author.) 


in  the  Pacific  Ocean;  M.  cavendishi  from  China;  M.  ensete  from  Africa.  The 
M.  sapientum  is  the  common  banana  plant  or  plantain.  According  to  Dr.  Royle, 
who  experimented  with  some  Indian  varieties  of  the  structural  fibre,  its  strength 
is  very  satisfactory.  His  results  are  as  follows:  A  Madras  specimen  bore  a  weight 
of  190  Ibs.,  while  one  from  Singapore  stood  360  Ibs.,  and  Russian  hemp  bore  190 
Ibs.  A  i2-thread  rope  of  plantain  fibre  broke  with  864  Ibs.,  when  a  single  rope 
of  pineapple  broke  with  924  Ibs.  Compared  with  English  and  Manila  hemps,  a 
rope  3^  inches  in  circumference  and  2  fathoms  long  gave  the  following  results. 
The  plantain,  dry,  broke  at  2330  Ibs.  after  immersion  in  water  24  hours;  tested 
7  days  after  2387  Ibs.,  and  after  10  days  immersion  2050  Ibs.  Manila  and  English 
hemp,  dry,  gave  4669,  and  3885  Ibs.  respectively. 


JUTE,  RAMIE,  HEMP,  AM)   MINOR  VEGETABLE   FIBRES     439 

9.  Sisal  Hemp  is  the  fibre  obtained  from  the  leaves  of  the 
Agave  rigida,  a  native  of  Central  America;*  it  is  also  grown  in 
the  islands  of  the  West  Indies  and  in  Florida,  f 

The  true  sisal  hemp  of  Florida  is  the  Agave  rigida,  but  there 
is  also  a  false  sisal  hemp  from  Florida,  which  is  frequently 
confused  with  the  other.  This  false  sisal  hemp  is  obtained 
from  Agave  decipiens,  which  is  found  wild  along  the  coast 
and  Keys  of  the  Florida  peninsula.  There  is  considerable  dif- 
ference in  the  habit  of  A.  decipiens  and  A.  rigida;  the  former 
throws  out  its  mass  of  leaves  from  the  top  of  a  foot-stalk  the 
leaves  radiating  like  a  star,  and  the  color  being  in  strong  contrast 
with  the  surrounding  vegetation.  The  true  sisal  plant,  on  the 
other  hand,  sends  up  its  leaves  from  the  surface  of  the  ground. 
The  leaf  of  the  A.  decipiens  is  also  shorter  and  narrower,  and 
nearly  always  rolled  in  at  the  sides,  so  that  the  cross-section 
appears  like  the  letter  U;  the  color  is  a  bright  green;  the 
leaf  also  possesses  very  strong  and  sharp  spines.  The  leaf  of 
the  A.  rigida  is  flatter  in  shape,  has  a  dark  green  color,  and  is 
without  spines.  With  respect  to  the  fibre  of  the  two  varieties, 
that  of  the  A.  decipiens  is  whiter,  finer,  softer,  and  greatly 
deficient  in  strength.  Tampico  hemp,  or  Mexican  fibre,  is 
obtained  from  another  variety  of  Agave  known  as  A.  heteracantha. 
It  is  a  structural  fibre  like  the  others  derived  from  the  leaves. 
It  is  stiff,  harsh,  and  bristle-like  though  pliant,  and  is  used  as  a 
substitute  for  animal  bristles  in  the  manufacture  of  cheap  brushes. 
The  parenchyma  or  pith  of  the  leaf  squeezed  out  in  the  extraction 

*  The  fibre  of  the  Agave  was  probably  used  by  the  ancient  Mexicans  and 
Aztecs.  Cloth  woven  from  this  fibre  was  known  as  "  nequen,"  and  it  is  interest- 
ing to  know  that  the  Yucatan  name  for  the  commercial  sisal  hemp  at  the  present 
time  is  "  henequen." 

t  The  commercial  supply  of  sisal  hemp  is  produced  in  Yucatan,  only  small 
quantities  being  grown  in  Cuba  and  the  Bahamas.  According  to  Semler  the 
natives  cultivate  seven  varieties  of  the  plant  of  which  Chelem  (A.  sisalana), 
Yascheki  (Agave  sp.)  and  Sacci  are  the  most  important,  while  Cajun  or  Cajum 
(Fourcroya)  cubensis  and  (F.  gigantea}  yield  only  coarse  fibres.  Giirke  (Notizbl. 
k.  Bot.  Gartens,  Berlin,  1896,  No.  4),  however,  has  shown  that  Agave  rigida  and 
its  variety  sisalana,  as  well  as  A .  elongata,  yield  true  sisal  hemp,  while  Fourcroya 
gigantea  (F.  foetida)  yields  Mauritius  hemp,  which  previously  was  regarded  as  a 
product  of  certain  species  of  Aloe. 


440  THE  TEXTILE  FIBRES 

of  the  fibre  is  used  as  a  substitute  for  soap,  as  it  possesses  remark- 
able detergent  properties.  In  Mexico  the  fibre  is  commonly 
known  as  "  istle." 


A  B 

FIG.  in. — True  and  False  Sisal.     A,  leaves  of  true  sisal  hemp  plant;    B,  leaves 
of  false  plant  showing  thorny  edges.     (After  Bulletin  U.  S.  Dept.  Agric.) 

Sisal  has  a  light  yellowish  color,  and  is  very  straight  and 
smooth;    it  is  principally  used  for  making  cordage,  for  which 


JUTE,  RAMIE,  HEMP,  AM)   MINOR  VEGETABLE  FIBRES     441 


purpose  it  is  quite  valuable,  as  it  is  second  only  to  Manila  hemp 
in  tensile  strength.  The  fibre  is  easily  separated  from  the  leaf, 
and  does  not  require  a  retting  process.*  In  their  microscopical 
appearance  the  fibre  bundles  often  show  an  interlaced  formation 
with  a  peculiar  spiral  vessel  and  parenchyma  cells  containing 
single  calcium  oxalate  crystals,  which  are  often  quite  large. 


\ 


FIG.  ii2. — Florida  Sisal  Hemp.     Agave  decipiens.     (After  Dodge.) 

*  Sisal  hemp  is  cleaned  from  the  leaves  by  machines  which  scrape  out  the 
pulp  and  at  the  same  time  wash  the  fibre  in  running  water.  It  is  then  hung  in 
the  sun  to  dry  and  bleach  for  from  one  to  three  days,  after  which  it  is  baled  for 
market.  More  than  600,000  bales,  averaging  about  360  Ibs.  each,  were  imported 
by  the  United  States  during  1903;  the  price  during  the  past  decade  has  varied 
from  2f  to  10  cents  per  pound.  Sisal  fibre  of  good  quality  is  of  a  slightly  yellowish 
color,  2 \  to  4  feet  in  length,  somewhat  harsher  and  less  flexible  than  Manila 
hemp,  but  next  to  that  the  strongest  and  most  extensively  used  hard  fibre.  It  is 
used  in  the  manufacture  of  binder  twine,  lariats,  and  general  cordage,  aside  from 
marine  cordage  and  derrick-ropes.  It  cannot  withstand  the  destructive  action 
of  salt  water,  and  its  lack  of  flexibility  prevents  it  from  being  used  to  advantage 
for  running  over  pulleys  or  in  power  transmission.  It  is  extensively  used  in 
mixtures  with  Manila  hemp.  (Yearbook  Dept.  Agric.,  1903.) 


442  THE  TEXTILE  FIBRES 

The  fibre  elements  are  from  1.5  to  4  mm.  in  length  and  from 
20  to  32  pi  in  breadth,  the  ratio  of  the  length  to  the  diameter 
being  about  i :  100.  They  are  usually  quite  stiff  in  texture,  and 
show  a  remarkable  broadening  toward  the  middle.  The  width 
of  the  lumen  is  frequently  greater  than  that  of  the  cell-wall. 
The  ends  are  broad,  blunt,  and  thick,  but  seldom  forked.  The 
cross-sections  are  colored  yellow  by  iodin  and  sulphuric  acid, 


FIG.    113.— Sisal  Hemp.    '(Xsoo.)     W,   cell-wall;    P,   end  of  fibre;     S,   spiral- 
shaped  sclerenchymous  tissue.     (Micrograph  by  author.) 


and  show  no  evidence  of  a  median  layer  between  the  elements. 
The  sections  are  polygonal  in  outline,  but  often  have  rounded 
edges,  and  the  bundles  are  usually  close  together.  The  lumen 
in  the  cross-section  is  large  and  polygonal  in  shape,  though  the 
edges  of  the  lumen  are  more  rounded  than  those  of  the  walls. 
Short  thick-walled  fibres  with  short-pointed  ends  are  present 
m  large  numbers  in  sisal  hemp.  They  show  a  narrow  lumen 
and  distinct  surface  pores. 


Jl'TE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     443 

The  ash  obtained  from  the  ignition  of  the  fibre  shows  the 
presence  of  glistening  crystals  of  calcium  carbonate,  which  are 
derived  from  the  original  crystals  of  calcium  oxalate  to  be  found 
clinging  to  the  fibre  bundles.*  They  are  usually  in  longitudinal 
series,  about  0.5  mm.  long,  and  taper  off  at  the  ends  to  a  chisel 
shape,  resembling  a  thick  needle  in  form,  but  having  a  quadri- 
lateral cross-section. 

Sisal  hemp  (and  also  pita)  is  employed  as  a  substitute  for 
Manila  hemp  in  the  manufacture  of  cordage.  It  is  also  used 
for  the  making  of  brushes  and  as  a  substitute  for  horsehair. 

10.  Aloe  Fibre,  or  Mauritius  Hemp,  is  obtained  from  the 
leaf  of  various  species  of  aloe  plants  growing  in  tropical  climates,  t 
The  principal  plant  employed  for  Mauritius  fibre  is  Fourcroya 
fcetida.  In  Porto  Rico  it  is  known  as  maguey,  but  is  not  to  be 
identified  with  the  Mexican  fibre  of  the  same  name;  in  Hawaii 
it  is  called  malino,  which  is  probably  a  corruption  of  manila. 
The  only  locality  in  which  the  fibre  is  produced  commercially 
is  the  island  of  Mauritius.  This  fibre  is  often  confounded  with 
that  of  the  Agave  americana,  but  it  is  of  different  origin.  Aloe 
fibre,  however,  is  very  similar  to  Sansevieria  fibre,  and  is  hardly 
to  be  distinguished  from  it  in  either  physical  or  microscopic 
appearance.J  The  fibre  elements  are  from  1.3  to  3.7  mm.  in 
length  and  from  15  to  24  ^  in  breadth.  Although  uniformly 
broad,  the  cell- wall  is  thin.  The  fibres  are  usually  cylindrical 
and  not  flattened;  they  show  occasional  fissure-like  pores 
(see  Fig.  114).  The  cross-sections  are  polygonal,  with  slightly 
rounded  edges.  The  lumen  is  usually  somewhat  broader  than 
the  walls,  and  in  the  cross-section  is  polygonal  with  rounded 

*  The  occurrence  of  these  crystals  is  very  characteristic  of  this  fibre.  On  the 
coarse  fibres  employed  for  the  manufacture  of  brushes  the  crystals  may  frequently 
be  seen  with  the  naked  eye. 

t  The  commercial  supply  of  aloe  fibre  is  obtained  from  Africa. 

J  The  fibre  is  whiter  and  softer  than  other  hard  fibres,  but  it  is  weaker  than 
sisal.  It  is  used  in  the  manufacture  of  gunny  bags,  halters,  and  hammocks, 
but  more  largely  for  mixing  with  Manila  and  sisal  in  making  medium  grades  of 
cordage.  When  the  better  grades  of  cordage  fibre  (Manila  and  sisal)  are 
abundant  and  quoted  low  in  the  market,  Mauritius  is  likely  to  fall  below  the 
cost  of  production  (Yearbook,  Dept.  Agric.,  1903). 


444  THE  TEXTILE  FIBRES 

sides.  In  the  Sansevieria  fibre  the  lumen  in  the  cross-section 
is  usually  larger,  and  the  cell-walls  consequently  thinner;  fur- 
thermore the  lumen  has  a  sharp-edged  polygonal  form  (see  Fig. 
122). 

ii.  Pita  Fibre  is  obtained  from  the  leaf  of  the  Agave  ameri- 
cana  or  century  plant;  it  is  also  known  as  aloe  fibre. 

The  Agave  is  a  genus  of  fleshy-leaved  plants  belonging 
to  the  Amaryllidacea,  chiefly  found  in  Mexico  and  Central 


FIG.  114. — Mauritius  Hemp.     (Xsoo.)     (Micrograph  by  author.) 

and  South  America.  They  are  called  "  century  "  plants  because 
they  flower  but  once.  From  some  of  the  Mexican  species 
there  is  obtained  a  distilled  liquor  known  as  mescal,  also  the 
fermented  beverage  called  pulque.  The  fibre  from  A.  amer- 
icana  (maguey  plant)  is  a  structural  fibre  composed  of  large 
filaments  readily  separated  by  friction.  According  to  Spon  the 
agave  requires  about  three  years  to  come  to  perfection,  but 
it  is  exceedingly  hardy,  easy  of  cultivation,  and  very  prolific, 
and  grows  in  arid  wastes  where  scarcely  any  other  plant  can 


JUTE,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE  FIBRES     445 

live.  It  perishes  after  inflorescence,  then  sends  up  numerous 
shoots.  In  Mexico  5000  to  6000  plants  may  be  found  on  an 
acre;  the  average  number  of  leaves  is  40,  each  measuring  8 
to  10  feet  in  length  and  i  foot  in  width,  and  yielding  6  to  10 
per  cent  by  weight  of  fibre. 

There  are  several  varieties  of  agave  fibre,  which  are  known 
by  their  Mexican  or  Indian  names.  The  best  known  of  these 
are  the  henequen  (Agave  saxi),  the  ixtle  (Agave  americana), 


FIG.  115. — Fibre  from  Aloe  speciosus.     (X325.)     e,  ends;    /.  longitudinal  view; 
q,  cross-section;     r,  fissure-like  pores  in  cell- walls.     (Hohnel.) 

and  the  lechuguilla  (Agave  heteracantha) .  The  latter  is  also 
known  as  Tampico  or  Matamoros  hemp.  The  henequen  is 
principally  grown  in  Yucatan,  and  was  extensively  used  and 
highly  prized  by  the  ancient  Mexicans,  and  still  is  at  the  present 
time.  In  recent  years  it  has  been  quoted  in  European  markets 
at  $7.30  per  100  Ibs.  The  fibre  is  white  to  pale  straw  in  color, 
is  stiff  and  short,  has  a  rather  thin  wall,  and  furthermore  is 
liable  to  rot.  The  fibres  have  a  distinctive  wavy  appearance, 
and  another  peculiarity  is  its  great  elasticity.  According  to 
Royle,  Indian  pita  has  been  found  superior  in  strength  to 


446  THE  TEXTILE   FIBRES 

either  coir,  jute,  or  sunn  hemp,  the  breaking  strain  on  similar 
ropes  made  of  these  materials  being  as  follows: 

Pounds. 

Pita 2519 

Coir 2175 

Jute.  .  .  2456 

Sunn  hemp . 2269 

Russian   hemp  and  pita,   on   comparison,   gave   a   relative 
strength  of  16  to  27.     Besides  its  use  as  a  cordage  fibre,  pita 


FIG.  116. — Pita  Fibre.     (Xsoo.)     Agave  americana.     (Micrograph  by  author.) 

is  also  employed  for  the  making  of  a  very  delicate  and  beautiful 
lace  known  as  Fayal.  In  its  microscopical  characteristics 
pita  is  very  similar  to  sisal  hemp. 

12.  Pineapple  Fibre,  or  Silk  Grass,*  is  obtained  from 
Ananas  saliva  or  pineapple  plant.  This  fibre  has  great  durability 
and  is  unaffected  by  water.  It  is  very  fine  in  staple  and  highly 

*  The  terra  "  silk  grass,"  though  applied  to  this  fibre,  is  both  meaningless  and 
a  misnomer. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     447 

lustrous,  and  is  white,  soft,  and  flexible.  It  is  used  in  the 
manufacture  of  the  celebrated  pina  cloth  in  the  Philippine 
Islands.  According  to  Taylor,  a  specimen  of  this  fibre  was 
subdivided  to  one  ten-thousandth  of  an  inch  in  thickness,  and 
was  considered  to  be  the  most  delicate  in  structure  of  any  known 
vegetable  fibre.  'Microscopically  it  is  distinguished  from  all 
other  leaf  fibres  by  the  extreme  fineness  of  its  fibre  elements. 


FIG.  117. — Pineapple  Plant.     (After  Dodge.) 

These  are  from  3  to  9  mm.  in  length  and  from  4  to  8  pi  in  thick- 
ness. The  lumen  is  very  narrow  and  appears  like  a  line.  The 
cross-sections  are  polygonal  in  outline  and  frequently  flattened. 
The  sections  form  in  compact  groups  which  are  often  crescent- 
shaped,  and  are  enclosed  in  a  thick  median  layer  of  lignified 
tissue. 

13.  Coir  Fibre  is  obtained  from  the  fibrous  shell  of  the  cocoa- 
nut.  For  the  preparation  of  the  fibre,  the  unripe  nuts  are  steeped 
in  sea-water  for  several  months,  after  which  the  fruit  is  beaten 


448 


THE  TEXTILE  FIBRES 


and  washed  away  with  water.  The  residual  reddish  brown 
fibrous  mass  is  decorticated  by  tearing  and  heckling  into  fibres 
about  10  inches  in  length.  The  fibre  occurs  in  the  form  of 
large,  stiff,  and  very  elastic  filaments,  each  individual  of  which 
is  round,  smooth,  and  somewhat  resembling  horsehair.  It 
is  principally  used  for  making  mats  and  cordage.  It  possesses 
remarkable  tenacity  and  curls  easily.  In  color  it  is  cinnamon 
brown.  It  possesses  marked  microscopical  characteristics; 
the  fibre  elements  are  short  and  stiff,  being  from  0.4  to  i  mm. 
in  length  and  from  1 2  to  24  pi  in  diameter,  the  ratio  of  the  length 


FIG.  118. — Section  of  Cocoanut.     (1/5.)     a,  husk  containing  fibre;    b,  the  fruit 
or  edible  portion.     (After  Bulletin  U.  S.  Dept.  Agric.) 

to  the  thickness  is  only  35.  The  cell- wall  is  thick,  but  rather 
irregularly  so,  in  consequence  of  which  the  lumen  has  an 
irregularly  indented  outline  (see  Fig.  119).  The  points  termi- 
nate abruptly  and  are  not  sharp,  and  there  appear  to  be  a 
large  number  of  pore-canals  penetrating  the  cell- wall.  On 
the  surface  the  fibre  bundles  are  occasionally  covered  with 
small  lens-shaped,  silicified  stegmata,  about  15  pi  in  breadth. 
These  stegmata  fuse  together  on  ignition,  giving  a  blister  on 
the  ash.  If  the  fibre  is  boiled  with  nitric  acid  previous  to  its 
ignition,  the  stegmata  then  appear  in  the  -ash  like  yeast-cells 
hanging  together  in  the  form  of  round,  silicious  skeletons. 


JITK,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE  FIBRES     449 

Coir  gives  the  following  microchemical  reactions:  with 
iodin  and  sulphuric  acid,  golden  yellow;  with  anilin  sulphate, 
intense  yellow;  Schweitzer's  reagent  does  not  attack  the  fibre. 


Si 

FIG.  119. — Coir  Fibre.     (X3oo.)     s,  serrations  in  wall  of  lumen;   p,  pores  in  wall; 
Si,  silicious  skeleton  from  stegmata.     (Micrograph  by  author.) 

These  reactions  indicate  a  lignified  fibre.     According  to  Schlesin- 
ger,  coir  contains  20.6  per  cent  of  hygroscopic  moisture. 

The  cross-section  of  the  fibre  is  oval  in  shape  and  yellowish 
brown  in  color,  and  enclosed  in  a  network  of  median  layers. 


FIG.  120. — Coir  Fibre.     (X3oo.)     (Micrograph  by  author.) 

Coir  fibre  is  employed  in  the  South  Seas  instead  of  oakum  for 
caulking  vessels,  and  it  is  claimed  that  it  will  never  rot.  -The 
principal  use  for  coir,  however,  is  for  cordage  and  matting. 


450  THE   TEXTILE  FIBRES 

For  cable-making  it  is  said  to  be  superior  to  all  other  fibres, 
on  account  of  its  resistance  to  water,  lightness  and  great 
elasticity.  It  also  has  a  great  resistance  to  mechanical  wear. 
Wright  gives  the  following  tests  on  various  cordage  fibres: 

Pounds. 

Hemp 190 

Coir 224 

Bowstring  hemp 316 

14.  Istle  Fibre,  otherwise  known  as  Tampico  fibre,  is 
obtained  from  the  leaves  of  several  species  of  Mexican  plants 
which  are  principally  found  in  the  desert  table-lands  of  northern 
Mexico.  The  most  important  istle  fibres  are  Jaumave  lechu- 
guilla, Jaumave  istle,  lechuguilla,  Tula  istle,  Palma  samandoca, 
and  Palma  pita.*  The  principal  plants  yielding  the  fibre  are 
Agave  heteracantha,  A.  lechuguilla,  and  Samuella  carnerosana. 


FIG.  121. — A  Leaf  of  Agave  heteracantha.     (After  Bulletin  U.  S.  Dept.  Agric.) 

Istle  fibre  is  used  largely  for  making  brushes;  it  is  also 
made  into  cordage  and  woven  into  coarse  sacks  for  containing 
grain.  The  commercial  fibre  is  from  12  to  30  inches  in  length, 
and  is  coarse  and  harsh.  The  color  of  the  fibre  is  deep  yellow, 
but  on  boiling  with  water  this  coloring  matter  is  almost  alto- 

*  Palma  istle  fibre  is  15  to  35  inches  in  length,  usually  coarser  and  stiff er  than 
sisal,  yellow  in  color,  and -somewhat  gummy.  Tula  istle  is  12  to  30  inches  long 
and  nearly  white  in  color.  Jaumave  istle  is  20  to  40  inches  long,  rarely  longer, 
almost  white,  and  nearly  as  strong  and  flexible  as  sisal.  The  importations  of 
istle  fibre  into  the  United  States  had  increased  from  less  than  4000  tons  in  1900 
to  more  than  12,000  tons  in  1903.  Istle  fibre  has  long  been  used  as  a  substitute 
for  bristles  in  the  manufacture  of  brushes,  and  it  is  now  being  employed  in  increas- 
ing quantities  in  the  cheaper  grades  of  twine,  such  as  lath  twine,  baling  rope,  and 
medium  grades  of  cordage.  Introduced  at  first  as  an  adulterant  or  substitute  for 
better  fibres,  it  seems  destined  to  find,  through  improved  processes  of  manufac- 
ture, a  legitimate  place  in  the  cordage  industry.  If  machines  are  devised  for 
cleaning  this  fibre  in  a  satisfactory  manner,  it  is  thought  that  the  thousands  of 
acres  of  lechuguilla  plants  in  western  Texas  may  be  profitably  utilized. 


JITK.  KAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     451 

gather  removed.  The  parenchymous  tissue  separated  from  the 
fibre  is  used  as  a  substitute  for  soap,  and  even  the  commercial 
fibre  gives  a  soapy  solution  when  boiled  with  water. 

15.  Nettle  Fibre.* — This  fibre  is  used  to  some  extent  for 
spinning,  being  cultivated  for  this  purpose  in  certain  parts  of 
Germany  and  in  the  province  of  Picardy  in  France.  The  prod- 
uct known  by  the  specific  name  of  nettle  fibre  is  obtained  from 
two  species  of  the  stinging  nettle,  f  Urtica  dioica  and  Urtica 
urena.  The  Bcehmeria  (see  Ramie  and  China  grass)  are  also 
nettle  plants,  but  belong  to  the  stingless  variety.  The  Urtica 
dioica  yields  the  largest  amount  of  fibre,  but  of  large  diameter 
and  very  thin  cell- wall;  the  fibres  from  the  second  species, 
Urtica  urena,  are  much  smaller  in  diameter  and  have  a  thick 
cell-wall,  resembling  linen  fibres  to  a  great  extent;  its  chief 
drawback  is  the  small  yield  of  fibre  from  the  plant. 

The  nettle  fibre  appears  to  consist  of  pure  cellulose,  with 
occasional  traces  of  lignin  on  the  surface.  It  gives  the  following 
microchemical  reactions:  (a)  with  iodin-sulphuric  acid  reagent, 
blue  coloration;  {  (6)  with  ammoniacal  fuchsin  solution,  no 
coloration;  (c)  with  sulphate  of  anilin,  no  coloration;  (d)  with 
chlor-iodide  of  zinc,  bluish  violet  coloration;  (e)  with  chlor- 
iodide  of  calcium,  rose-red  coloration. 

The  fibres  of  Urtica  dioica  vary  in  length  from  5  to  55  mm. 
(Vetillart)  and  in  diameter  from  0.020  to  0.080  mm.  Under 
the  microscope  the  fibres  are  characterized  externally  by  fine 
oblique  striations;  the  ends  of  the  fibres  are  finely  pointed. 

The  cross-sections  of  the  fibres  are  oval  and  show  thin 
cell-walls,  which,  however,  at  times  may  become  quite  thick, 

*  See  Wiesner,  Rohstofe  des  Pflanzenreiches,  vol.  2,  p.  214;  Moller,  Die  Nessel- 
faser,  Poly  tec  hnische  Zeitung,  1883;  Hohnel,  Mikroskopie  der  Faserstoffe,  p.  52; 
Dodge,  Useful  Fibre  Plants,  p.  323. 

fThe  stinging  nettle  is  also  common  in  the  United  States;  it  grows  principally 
on  waste  lands.  It  has  not  been  used  as  a  fibre  plant  in  this  country  however. 
In  Sweden  it  is  cultivated  to  some  extent  for  its  fibre,  being  known  as  Swedish 
hemp;  it  is  used  for  cordage,  cloth,  and  fish-lines.  In  India  it  is  known  as  Bichu 
or  Chicru,  meaning  scorpion  or  stinger. 

\  The  lumen  of  the  fibre,  especially  toward  the  ends,  is  often  filled  with  mat- 
ter which  gives  a  yellow  color  with  this  reagent. 


452  THE  TEXTILE  FIBRES 

owing  to  irregularities  in  the  structure  of  the  fibre.  The 
fibre  is  supple,  long,  and  soft  to  the  touch;  like  ramie  it  pos- 
sesses great  resistance  to  water;  it  is,  however,  comparatively 
weak  in  strength,  owing  to  the  thin  cell-wall  and  irregular 
structure. 

On  account  of  the  thin  cell-wall,  the  nettle  fibre  gives  only 
faint  colorations  when  viewed  under  polarized  light.  In  Ger- 
many the  nettle  fibre  is  spun  into  a  greenish  colored  yarn  known 
as  Nesselgarn,  this  is  woven  into  a  cloth  called  Nesseltuch, 
which  may  be  bleached  to  a  pure  white,  and  much  resembles 
linen  cloth. 

16.  Fibre  of  Urena  Sinuata. — The   plant   from   which   this 
fibre   is  obtained  is  a   small   shrub   growing   generally  in  the 
tropics.     In  America  it  is  known   as  Caesar  weed;    in  Vene- 
zuela it  goes  by  the  name  of  Cadilla.     The  bast  fibre  resembles 
jute  in  appearance,  it  being  yellowish  in  color,  of  considerable 
brilliancy,  and  also  like  jute  it  deteriorates  in  moist  air.     The 
average  length  of  fibre  bundles  is  6  feet.     The  fibre-cells,  accord- 
ing to  Wiesner,  have  a  length  of  about  1.8  mm.,  and  an  average 
diameter  of  15  \L.     The  lumen  of  the  fibre  is  very  irregular  in 
width,  but  is  mostly  rather  broad,  though  not  so  large  as  that 
of  jute.     With  iodin  and  sulphuric  acid  the  fibre  gives  a  yellow 
color;   anilin  sulphate  also  gives  a  deep  yellow,  which  indicates 
strong   lignification ;     Schweitzer's   reagent   produces   a   strong 
swelling  of   the   cell-wall.     There   may  often  be   observed   on 
Urena  fibres,  under  the  microscope,  cells  of  parenchymous  tissue 
containing  crystalline  deposits.     The  ash  of  the  fibre  also  shows 
aggregates  of  calcium  carbonate,  a  feature  which  distinguishes 
it  from  jute. 

17.  Sansevieria  Fibres. — There  are  several  species  of  plants 
of  the  Sansevieria  group  which  are  used  for  fibre  purposes,  of 
which   the   following   are   the  principal   varieties:     Sansevieria 
cylindrica^  known  as  Iff  hemp;    it  occurs  in  South  Africa,  and 
the  fibre  is  used  for  cordage.     It  is  said  to  be  especially  adapted 
for  cordage  used  in  deep-sea  soundings.     S.  guineensis,  known 
as  African  bowstring  hemp,  is  grown  in  Guinea  and  in  tropical 
America.     The  fibre  somewhat  resembles  Manila  hemp  and  is 


JUTK,  RAMIE,  HEMP,  AND   MINOR  VEGETABLE   FIBRES     453 


used  for  cordage.  S.  kirkii,  known  as  Pangane  hemp;  it 
grows  on  the  mainland  opposite  the  island  of  Zanzibar;  the 
fibre  is  very  long  and  is  used  extensively  by  the  natives.  S. 
longiflora,  known  as  Florida  bowstring  hemp;  the  fibre  is 
strong  and  of  very  desirable  qualities,  and  is  said  to  be  superior 
to  sisal  hemp.  It  is  sufficiently  fine  to  be  employed  as  a  spinning 
fibre.  S.  roxburghiana  is  grown  in  India,  where  it  is  known 
as  Moorva.  It  gives  the  true  "  bowstring  hemp,"  as  the  fibre 
is  highly  prized  by  the  natives  for  bowstrings  on  account  of  its 


FIG.    122. — Fibre   from   Sansemeria.     (X325.)     e,   ends;    /,    longitudinal   view; 
q,  cross-section;     r,  fissure-like  pores  in  cell-walls.     (Hb'hnel.) 

great  strength  and  elasticity.  S.  zeylanica  is  a  species  cultivated 
in  Ceylon.  The  fibre  is  shorter  than  other  varieties,  but  is 
largely  used  for  making  cordage,  mats,  and  coarse  cloth. 

The  Sansevieria  fibres  are  all  obtained  from  the  leaves  of 
the  plants;  these  vary  in  length  from  2  to  9  feet.  The  com- 
mercial fibre  consists  of  a  bundle  of  filaments.  The  fibre  ele- 
ments have  a  length  of  about  2  mm.  and  a  diameter  of  about 
20  (L,  and  are  characterized  by  a  large  lumen.  The  fibres  are 
lignified  and  are  often  accompanied  by  spiral-shaped  cells  of 


454  THE  TEXTILE  FIBRES 

parenchymous  tissue.  In  strength  and  durability  Sansevieria 
fibre  is  almost  equal  to  Russian  hemp.  The  fibre  of  S.  zeylanica 
is  very  similar  to  aloe  or  Mauritius  hemp,  and  is  often  called 
"  aloe  hemp." 

18.  Tillandsia  Fibre. — This  fibre,  known  as  Spanish  moss,  is 
obtained  from  Tillandsia  usneoides,  and  is  extensively  employed 
in  trade  as  a  vegetable  horsehair,  as  it  resembles  very  closely  the 
animal  product  in  general  appearance,  durability,  and  elasticity. 
The  plant  grows  as  a  parasite  on  tropical  trees,  and  the  commer- 
cial product  consists  of  the  branched  stems.     It  is  of  a  greenish 
gray  color  and  is  covered  with  soft  silvery-gray  scales.     The  fibre 
is  composed  of  a  layer  of  bast  in  which  are  imbedded  eight  fibre 
bundles;   by  treatment  with  caustic  alkali  solution  the  nucleus 
(or  stripped  fibre)  is  easily  separated.     The  stripped  fibre  has  a 
jointed  appearance,   and   from   the  joints   side  branches  often 
issue.     According  to  Wiesner  the  commercial  fibre  never  has 
natural  ends;   the  color  varies  from  brown  to  lustrous  black. 
The  diameter  between  the   joints  varies  from   120   to   210  [L. 
The  diameter  of  the  commercial  fibre  is  from  0.3  to  0.5  mm. 
Microchemical    color    reactions  cannot    be  obtained  with  this 
fibre  owing  to  its  dark  color.     Schweitzer's  reagent  has  appar- 
ently no  reaction.    'According  to  Wiesner  the  fibre  of  vegetable 
horsehair  has  9.0  per  cent  of  moisture  and  3.21  per  cent  of  ash. 

19.  Fibre  of  Sea  Grass. — This  is  the  fibre  of  Zoster  a  marina, 
a  seaweed  or  grass  which  is  to  be  found  extensively  on  the 
seasoast  of  temperate  climates.     The  available  fibres  are  from 
i  to  2  feet  in  length,  and  consist  of  bundles  of  3  to  6  elements. 
The  latter  are  about  3  mm.  in  length,  with  a  diameter  of  about 
6  pt,  hence  they  are  of  great  fineness.     They  apparently  consist 
of  pure  cellulose. 

20.  Raphia.* — This  fibre  is  obtained  from  the  cuticle  of  the 
leaves  of  the  raphia  palm  (Raphia  ruffia),  which  grows  extensively 
in  Africa.     The  leaves  are  very  long,  the  average  being  about  25 
feet.     The  fibre  occurs  in  the  form  of  flat  straw-colored  strips, 
3  to  4  feet  in  length  and  about  J  inch  in  width;  from  these  rib- 

*  Sometimes  spelled  "raffia." 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE   FIBRES     455 

bons  (which  are  largely  used  for  plaited  textiles)  the  individual 
fibres  may  be  separated  as  fine  filaments.  The  fibre  elements 
are  about  1.7  mm.,  in  length  and  14  pi  in  diameter.  Under  the 
microscope  the  surface  of  the  fibre  appears  irregular,  owing  to 
the  occurrence  of  fragments  of  parenchymous  tissue.  The 
lumen  is  about  one-fifth  the  diameter  of  the  fibre.  With  iodin 
and  sulphuric  acid  the  fibre  gives  a  yellow  coloration;  with 
chlor-iodide  of  zinc  a  similar  color;  with  phloroglucinol  and 


FIG.  123. — Raphia  Fibres.     (X3oo.)     E,  showing  spoon-like  end. 
(Micrograph  by  author.) 

hydrochloric   acid  a  reddish   coloration.     Schweitzer's   reagent 
causes  an  irregular  swelling  of  the  fibre. 

21.  Bromelia  Fibres. — The  Bromelia  is  a  genus  of  plants 
having  very  short  stems  and  densely  packed,  rigid,  lance-shaped 
leaves,  the  margins  of  which  are  armed  with  sharp  spines; 
they  are  natives  of  tropical  America,  though  also  found  in  other 
tropical  countries.  The  principal  species  which  yield  fibre 
are  the  following:  B.  karatas,  B.  pinguin,  B.  argentina,  B. 


456 


THE  TEXTILE  FIBRES 


fastuosa,  B.  sagenaria,  B.  sylvestris,  and  B.  serra.  In  Mexico 
the  Bromelia  is  cultivated  in  parts  as  a  textile  plant  and  a  fibre 
is  obtained  from  it  which  is  described  as  very  fine  and  from  6 
to  8  feet  in  length.  By  reason  of  its  fineness  and  toughness,  it 
is  used  for  making  belts,  and  such  fabrics  as  bagging,  wagon- 


FIG.  124. — Fibres  of  Bromelia  karatas.     (Xaoo.)     (Micrograph  by  author.) 

sheets,   carpets,   and   also   for   cordage,   hammocks,   etc.     The 
B.  pinguin  *  is  perhaps  the  best  known  of  this  class  of  fibre 

*Dr.  Baker  gives  the  botany  of  B.  pinguin  as  follows:  Acaulescent;  leaves 
100  or  more  in  a  rosette,  ensiform,  stiffly  erect  in  the  lower  half,  reaching  a  height 
of  5  or  6  feet,  i|  to  2  inches  broad  at  the  middle,  tapering  gradually  to  the  point, 
green  and  glabrous  on  the  face,  thinly  white-lepidote  on  the  back,  armed  with  very 
large-toothed  pungent  brown  prickles;  peduncle  stout,  stiffly  erect,  about  a  foot 
long,  its  leaves  often  a  bright  red;  panicle  dense,  stiffly  erect,  i  to  2  feet  long;  axis 
and  branches  densely  mealy;  branch-bracts  oblong,  pale,  lower  with  a  rigid  spine- 
edged  cusp;  lower  branches  3  to  4  inches  long,  bearing  6  to  8  sessile  flowers; 
flower-bracts  minute,  ovate;  ovary  cylindrical,  very  pubescent,  about  an  inch 
long;  sepals  nearly  as  long,  with  a  densely  matted  tip;  petals  reddish,  densely 
matted  at  the  tip  with  white  tomentum,  about  ij  inches  longer  than  the  calyx; 
berry  ovoid,  yellowish  brown,  i  inch  in  diameter. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     457 

plants,  and  it  is  known  as  the  wild  pineapple;  it  is  often  mistaken 
for  an  allied  species,  the  B.  sylvestris,  and  many  writers  have 
confused  both  of  these  varieties  with  the  fibre  of  the  common 
pineapple.  The  wild  pineapple  fibre  mentioned  by  Morris 
(of  the  Kew  Gardens)  as  B.  pita  is  really  B.  karatas. 

The  B.  argentina,  known  as  caraguata,  is  an  allied  species 
which  is  found  in  Argentina  and  Paraguay;  its  structural 
fibre  is  soft  and  silky  and  resembles  pineapple  fibre,  occurring 
in  lengths  of  from  4  to  6  feet  and  of  medium  strength.  The 
B.  sylvestris*  gives  a  structural  fibre  which  is  very  long,  creamy- 
white,  fine,  and  silky;  it  is  used  in  Central  America  for  making 
hunting  pouches  and  finely  woven  textures.  The  name  of 
"  silk  grass  "  and  "  silk  grass  of  Honduras  "  has  been  given 
to  this  species,  but  this  is  a  rather  indiscriminate  name  and  is 
applied  to  a  number  of  widely  differing  fibres.  Some  writers 
also  refer  to  this  fibre  as  the  "  istle  "  or  "  ixtle  "  of  Mexico. 
This  variety  is  also  given  the  name  Karatas  plumieri,  and  is 
commonly  known  as  Mexican  fibre,  Honduras  silk-grass,  and 
wild  pineapple.  The  plant  grows  throughout  tropical  America, 
and  the  fibre  is  obtained  from  the  leaf  which  grows  to  a  length 
of  8  to  10  feet  and  is  armed  with  recurved  teeth  or  spines.  This 
fibre  f  has  been  much  confused  with  that  of  Bromelia  sylvestris. 


*  Dr.  Baker  gives  the  following  description  of  the  botany  of  B.  sylvestris: 
Acaulescent;  leaves  ensiform,  rigid,  3  to  4  feet  long,  i£  inches  broad,  low  down, 
narrowed  gradually  to  the  point,  bright  green  on  the  face,  thinly  albo-lepidote  on 
tj?e  back,  armed  with  strong-hooked  prickles;  peduncle  a  foot  or  more  long,  its 
leaves  reflexing,  the  upper  bright  red;  inflorescence  a  narrow  panicle  with  short 
spaced-out  corymbose  branches,  all  subtended  by  bright  red  bracts,  the  lower 
with  rigid  spine-edged  tips;  ovary  pubescent,  cylindrical-trigonous,  about  an 
inch  long;  sepals  nearly  as  long  as  the  ovaries;  petals  reddish,  not  matted  at 
the  tip,  protruding  \  inch  from  the  calyx. 

t  The  botany  of  Karatas  plumieri  is  described  as  follows:  Acaulescent;  leaves 
30  to  40  in  a  dense  rosette,  rigid,  spreading,  ensiform,  4  to  8  feet  long,  \  to  2  inches 
broad,  low  down,  narrowed  gradually  to  the  tip*,  green  and  glabrous  on  the  face, 
persistently  white-lepidote  and  finely  lineate  on  the  back,  armed  with  large 
pungent-hooked  marginal  prickles;  flowers  about  50  in  a  dense  sessile  central 
capitulum,  at  first  3  to  4  inches,  finally  6  to  8  inches  in  diameter,  surrounded 
by  reduced  ensiform  inner  leaves  tinged  with  red;  flower-bracts,  scariose,  oblan- 
ceolate,  2\  to  3  inches  long;  ovary  cylindrical-trigonous,  i£  inches  long,  clothed, 
like  the  bracts  and  sepals,  with  loose  brown  tomentum;  sepals  linear,  permanently 


458  THE  TEXTILE  FIBRES 

The  fibre  appears  to  be  used  locally  only  for  nets,  cordage, 
sacking,  etc.  The  fibre  varies  in  quality  according  to  the  age  of 
the  plant,  that  from  the  young  leaves  being  fine  and  white, 
while  the  older  leaves  give  coarser  fibre.  It  has  been  pro- 
nounced by  some  as  being  superior  to  Russian  flax  as  a  textile 
fibre. 

22.  Piassava. — This  fibre  is  obtained  from  the  piassava  palm, 
growing  chiefly  in  Brazil.  There  are,  however,  two  varieties 
of  piassava;  the  Brazilian  is  obtained  from  the  leaves  of  Attalea 
funifera,  while  the  African  is  obtained  from  the  leaves  of  the 
wine  palm,  or  Raphia  vinifera.  In  Brazil  the  piassava  fibre 
is  extensively  used  for  the  making  of  ropes,  sails,  and  mats. 
At  the  present  time  it  is  also  largely  used  in  Europe  for 
the  manufacture  of  brushes,  it  being  of  the  nature  of  a  bristle,  yet 
very  flexible.  The  commercial  fibre  from  Brazil  has  a  length 
often  as  much  as  6  feet;  according  to  Wiesner  the  breadth  of 
the  fibre  is  0.8  to  3.5  mm.  The  color  varies  from  light  to  dark 
brown.  The  individual  bast  cells  are  0.3  to  0.9  mm.  in  length. 
Stegmata  are  often  observed  in  the  periphery,  and  on  treatment 
with  chromic  acid  the  silicious  matter  is  left  in  characteristic 
star-shaped  residues.  According  to  Greilach  air-dried  piassava 
contains  9.26  per  cent  of  moisture,  and  Wiesner  found  the  ash 
to  be  0.506  per  cent. 

African  piassava  has  less  elasticity  than  the  Brazilian  prod- 
uct, and  hence  is  of  lower  value.  In  cross-section  under  the 
microscope,  the  Brazilian  fibre  shows  an  aggregate  of  bundles, 
whereas  the  African  piassava  consists  of  a  single  filament. 
The  commercial  African  fibre  has  a  length  of  about  60  cms. 
and  a  breadth  of  i  to  3  mm.  (Wiesner).  The  color  varies  from 
pale  yellow  to  dark  brown.  The  stegmata  resemble  those  on 
the  Brazilian  fibre  but  are  larger. 

There  are  also  a  few  other  fibres  known  commercially  as 
piassava,  the  principal  one  of  which  is  obtained  from  Caryota 

erect,  an  inch  long;  petals  reddish,  glabrous,  exserted  \  to  \  inch  beyond  the  tip 
of  the  sepals,  united  in  a  tube  toward  the  base;  fruit  3  to  4  inches  long,  i  inch 
diameter,  pale  yellow,  with  an  edible  white  pulp,  tapering  from  the  middle  to 
both  ends;  seeds  globose,  dull  brown,  vertically  compressed,  |  inch  diameter. 


JUTE,  RAMIE,  HEMP,  AND  MINOR  VEGETABLE  FIBRES     459 

urens.  This  is  grown  in  India  and  Ceylon  and  is  known  by  the 
name  kitol  or  kittul  (see  p.  162).  It  is  used  as  a  substitute  for 
horsehair. 

23.  Textile  Yarns  from  Wood-pulp.  There  is  at  present 
a  considerable  industry  in  the  manufacture  of  yarns  for  twine 
and  textile  fabrics  from  wood-pulp.  The  wood-pulp  tissue 
is  cut  into  narrow  strips  which  are  then  twisted  on  special 
machines  so  as  to  give  a  coarse  yarn.  These  yarns  are  made 
in  counts  from  5  to  10  (cotton  scale)  and  are  possessed  of  suf- 
ficient tensile  strength  and  elasticty  to  be  manufactured  into 
a  wide  variety  of  fabrics.  Used  alone,  these  wood-pulp  yarns 
are  made  into  floor  coverings,  bagging,  wall  covering,  and  various 
ornamental  upholstery  fabrics.  They  are  especially  adapted 
as  a  substitute  for  jute  in  such  uses,  for  though  they  have  not 
the  tensile  strength  of  jute,  yet  they  exhibit  great  resistance  to 
wear  and  rubbing.  When  woven  in  conjunction  with  yarns 
of  cotton,  linen,  jute,  etc.,  a  wide  variety  of  fabrics  may  be 
cheaply  produced. 

The  manufacture  of  yarns  from  wood-pulp  allows  of  the 
utilization  in  the  purely  textile  industries  of  fibres  not  having 
sufficient  length  to  be  spun.  The  minimum  limit  of  economic 
working  is  obtained  in  spinning  with  fibres  of  3-5  mm.  length, 
and  as  this  is  the  maximum  limit  in  the  case  of  paper  making, 
it  may  be  seen  that  by  converting  paper  into  textile  yarns  it 
becomes  possible  to  utilize  for  the  latter  fibres  of  any  length. 

There  are  several  methods  now  in  use  for  the  manufacture 
of  wood-pulp  yarns: 

(a)  The  Claviez  System  *  makes  a  yarn  called  xylolin  from 
a  finished  but  unsized  paper.  The  paper  is  cut  into  strips  of 
2-3  mm.  width,  which  are  then  wound  on  separate  bobbins. 
A  twisting  and  rolling  is  then  given  the  paper  strip  so  as  to 
consolidate  it  into  a  compact  thread  or  yarn.  The  yarn  is 
then  moistened  and  again  twisted  and  rolled  to  produce  a  more 
solid  thread.  Textilose  is  a  similar  product  used  as  a  jute 
substitute. 

*  See  Ger.  Pat.  93,324.     The  Claviez  method  was  worked  at  Jagenberg. 


460  THE   TEXTILE   FIBRES 

(b)  The  Kellner-Tiirk  method  *  starts  with  the  paper  sheet 
in  the  unfinished  condition  as  it  is  delivered  from  the  press-rolls 
of  the  paper  machine.     The  production  of  the  pulp  ribbons  is 
effected  by  a  specially  constructed  wire  cloth  consisting  of  a 
gauze  alternating  with  flat  strips  of  brass.     The  pulp  ribbons 
are  then  rolled  and  twisted  into  a  yarn!t 

(c)  The  Kron  system  J  produces  products  known  as  sihalin 
yarns.     The  pulp  web  is  divided  into  narrow  strips  by  fine  jets 
of  water.      The  entire  web  is  rolled  up  and  the  strips  afterward 
separated  as  discs.     The  pulp  strips  are  then  squeezed  between 
press  rolls  for  the  gradual  removal  of  water,  then  further  dried 
on   steam-heated   cylinders.     The   strips   are   next   wound   on 
magazine  rolls  from  which  they  are  twisted  and  rolled  into  yarns. 
Silvalin  yarns  are  now  produced  in  large  quantities  in  Germany 
and  Russia  where  they  are  employed  as  substitutes  for  jute. 
Licella  yarn  is  a  similar  product  made  from  narrow  strips  of 
wood-pulp  paper  as  a  substitute  for  jute.  § 

According  to  Pfuhl  ||  wood-pulp  yarns  have  an  average 
breaking  length  of  5-7  km.,  and  an  elasticity  of  6-7  per  cent  of 
their  strength  when  moistened,  but  when  woven  into  fabrics 
they  may  be  waterproofed  satisfactorily.  The  finished  fabric 
has  about  one-half  the  strength  of  jute  fabric  of  the  same  quality 
and  weight. 

The  size  or  count  of  wood-pulp  yarns  is  expressed  by  the 
number  of  metres  to  the  gram.  To  convert  this  into  the  cotton 
count  (840  yds.  per  Ib.)  multiply  by  the  factor  0.691 ;  to  convert 
into  the  linen  count  (300  yds.  per  Ib.)  multiply  by  the  factor 
1.654;  and  to  convert  into  the  jute  count  (Ibs.  per  14,400  yds.) 
multiply  by  the  factor  29. 

*See  Ger.  Pat.  73,601,  and  76,126,  and  79,272.  The  Kellner-Turk  process 
is  carried  out  at  Altdamm,  Stettin. 

t  See  Ger.  Pat.  140,011  and  140,012.  and  140,666. 

|  See  U.  S.Pat.  762,914  an  794516;  762,640  and  762,641;  795,776  and 
776,474. 

§  Licella  yarn  is  made  by  fhe  Siiddeutschen  Jutefabrik. 

||  Pfuhl,  Papiersto/garne,  p.  101. 


CHAPTER  XVIII 
ANALYSIS  OF  THE  TEXTILE  FIBRES 

i.  General  Considerations. — In  a  commercial  examination 
of  manufactured  yarns,  fabrics,  etc.,  it  will  only  be  necessary 
to  distinguish  between  wool,  silk,  cotton,  linen,  jute,  hemp, 
and  ramie.  Under  wool  must  also  be  included  analogous 
animal  hairs,  such  as  mohair,  cashmere,  etc.  Other  animal 
fibres,  such  as  cow-hair  and  horse-hair,  may  easily  be  distin- 
guished even  by  the  naked  eye.  Of  course  there  are  numerous 
other  fibres  of  vegetable  origin  which  are  employed  more  or  less  for 
textile  materials,  but  either  they  are  not  liable  to  occur  in  con- 
junction with  the  above  fibres,  or  they  may  be  readily  distin- 
guished from  the  latter  without  requiring  a  special  examination. 
Dodge  gives  a  list  of  American  commercial  vegetable  fibres, 
the  total  number  of  which  is  about  30,  of  which  the  more  impor- 
tant are  as  follows: 
Six  bast  fibres: 

Flax,  Linum  usitatissimum. 
China  grass,  Boehmeria  nivea  and  B.  tenacissima. 
Hemp,  Cannabis  saliva. 
Jute,  Corchorus  capsularis  and  C.  olilorius. 
Sunn  hemp,  Crotalaria  juncea. 
Cuba  bast,  Hibiscus  tiliaceus. 

The  first  five  of  this  class  are  used  for  spinning  fibres,  while 
the  latter  finds  use  for  millinery  purposes. 
Two  surface  fibres: 

Cotton,  Gossypium  sp. 
Raphia,  Raphia  ruffia. 

461 


462 


THE  TEXTILE   FIBRES 


Cordage  fibres. 


Brush  fibres. 


Upholstery  and 
matting  fibres. 


Fifteen  structural  fibres,  representing  agaves,  palms,  and 
grasses: 

Sisal  hamp,  Agave  rigida 

Manila  hemp,  Musa  textilis 

Mauritius  hemp,  Fourcroya  gigantea 

New  Zealand  flax,  Phormium  tenaot 

Tampico  or  Istle,  Agave  heteracantha 

Bahia  piassave,  Attalea  funifera 

Para  piassave,  Leopoldinia  piassaba 

Mexican  whisk  or  Broom  root,  Epicampes 
macroura 

Cabbage  palmetto,  Sabal  palmetto 

Crin  vegetal,  Chamarops  humilis 

Spanish  moss,  Tillandsia  usneoides 

Saw  palmetto,  Serenoa  serrulata 

Cocoanut  fibre,  Cocos  nucifera 

Esparto  grass,  Stipa  tenacissima,  a  paper  fibre. 

Vegetable  sponge,  Luff  a  (Bgyptica,  a  substitute  for  sponge. 
The  native  vegetable  fibres  of  the  United  States  that  are 
produced    in    commercial    quantities   are    cotton,    hemp,    flax, 
palmetto  fibre,  and  vegetable  hair  from  Spanish  moss. 

The  best  method  of  distinguishing  qualitatively  between 
the  various  fibres  above  mentioned  is  by  the  use  of  the  micro- 
scope, whereby  their  characteristic  physical  appearance  may  be 
readily  observed.  Each  of  the  fibres  in  question  presents  cer- 
tain microscopical  peculiarities,  so  that  no  difficulty  is  encoun- 
tered in  distinguishing  between  them.  The  difference  in  the 
microscopical  appearance  of  these  fibres  may  be  comparatively 
observed  by  reference  to  the  figures  given  in  the  preceding 
pages. 

2.  Qualitative  Tests. — A  rough  physical  test  to  distinguish 
between  animal  and  vegetable  fibres  is  to  burn  them  in  a  flame. 
Vegetable  fibres  burn  very  readily  and  without  producing  any 
disagreeable  odor;  animal  fibres,  on  the  other  hand,  burn  with 
some  difficulty  and  emit  a  disagreeable  empyreumatic  odor 
resembling  that  of  burning  feathers.  The  burnt  end  of  the 
fibre  is  also  characteristic,  vegetable  fibres  burning  off  sharply 


ANALYSIS   OF  THE  TEXTILE  FIBRES 


463 


at  the  end,  whereas  animal  fibres  fuse  to  a  rounded,  bead-like 
end. 

Tables  I  and  II  exhibit  the  characteristic  chemical  reac- 
tions of  the  principal  fibres,  and  by  suitably  employing  these 
tests  the  principal  fibres  may  be  easily  distinguished  from  one 
another. 

The  reagents  employed  for  the  tests  in  the  tables  may  be 
prepared  as  follows: 

(1)  Madder  Tincture. — Extract    i   gm.   of   ground   madder 
with  50  cc.  of  alcohol,  and  filter  from  undissolved  matter. 

(2)  Cochineal  Tincture.— This  is  made  in  the  same  manner 
as  the  above,  using  i  gm.  of  ground  cochineal  insects. 

TABLE  I 


Test. 

Wool. 

Silk. 

Linen. 

Cotton. 

DYESTUFF  TESTS. 
Madder  tincture  

Nil 
Scarlet 
Red 
Dyed 

Nil 

Partly  diss. 
Nil 
Violet  to  brown 
Red  to  brown 
Black 
Black  ppt. 
Swells  only 
Undissolved 

Nil 
Scarlet 
Red 
Dyed 
Nil 

Dissolves 
Nil 
Nil 
Nil 
Nil 
No  ppt. 
Nil 
Dissolves 

Oran  e 
Violet 
Nil 
Nil 
Dyed 

Yellow 
Light  red 
Nil 
Nil 
Dyed 

Cochineal  tincture  
Fuchsin                         .  .  . 

Acid  dyes  in  general  
Mikado  yellow  

ACTION  OF  VARIOUS 
SALTS. 
Zinc  chloride  
Stannic  chloride      

Fibre  undiss.,  yellow  color 
Black  color 
Nil 
Nil 
Nil 
Nil 
Swells  and  partly  dissolves 
Undissolved 

Silver  nitrate 

Mercury  nitrate  (Millon's' 
Cupric  or  ferric  sulphate. 
Sodium  plumbite  
Ammoniacal  copper  oxide 
Ammoniacal  nickel  oxide  . 

(3)  Fuchsin  Solution. — Dissolve  i  gm.  of  fuchsin  (magenta) 
in  100  cc.  of  water,  then  add  caustic  soda  solution,  drop  by  drop 
until  the  fuchsin  solution  is  decolorized;  filter  and  preserve  in  a 
well-stoppered  bottle.  In  applying  the  test  with  this  reagent, 
the  mixed  fibres  are  treated  with  the  hot  solution,  then  well 
rinsed,  when  the  animal  fibres  will  be  dyed  red,  the  vegetable 
fibres  remaining  colorless. 


464  THE  TEXTILE   FIBRES 

(4)  Zinc    Chloride   Solution. — Dissolve    1000   gms.    of   zinc 
chloride  in  850  cc.  of  water,  and  add  40  gms.  of  zinc  oxide, 
heating  until  complete  solution  is  effected. 

(5)  Stannic  Chloride  Solution. — This  may  be  prepared   by 
dissolving  15  gms.  of  stannous  chloride  (SnCk)  in  15  cc.  of  con- 
centrated   hydrochloric    acid,    then    gradually   adding   3    gms. 
of  powdered  potassium  chlorate  (KClOs).     Dilute  to  100  cc. 
with  water. 

(6)  Silver  Nitrate  Solution. — 5  gms.  of  silver  nitrate  (AgNOs) 
are  dissolved  in  100  cc.  of  water,  and  preserved  in  an  amber- 
colored  bottle. 

(7)  Mercury  Nitrate,   Milton's  Reagent. — Dissolve   10  gms. 
of  mercury  in  25  cc.  of  nitric  acid  diluted  with  25  cc.  of  water 
at  a  lukewarm  temperature.     Mix  this  solution  with  one  of 
10  gms.  of  mercury  in  20  cc.  of  fuming  nitric  acid. 

(8)  Copper  Sulphate  or  Ferric  Sulphate. — Dissolve  5  gms.  of 
these  salts  respectively  in  100  cc.  of  water. 

(9)  Sodium  Plumbite. — Dissolve  5  gms.  of  caustic  soda  in 
100  cc.  of  water  and  add  5  gms.  of  litharge  (PbO),  and  boil 
until  dissolved. 

(10)  Ammoniacal  Copper  Oxide,  Schweitzer's  Reagent. — Dis- 
solve 5  gms.  of  copper  sulphate  in  100  cc.  of  boiling  water,  add 
caustic  soda  solution  till  the  copper  compound  is  completely 
precipitated,  wash  the  precipitate  of  copper  hydrate  well  then 
dissolve  in  the  least  quantity  of  ammonia  water.     This  gives 
a  deep  blue  solution. 

Bottcher  recommends  that  this  solution  be  prepared  as  fol- 
lows: A  glass  tube  about  2  inches  in  diameter  and  24  inches 
in  length  is  loosely  filled  with  thin  sheet  copper  and  then  filled 
up  with  ammonia  water.  After  a  few  minutes,  the  liquid  is 
drawn  off,  and  then  poured  over  the  copper  again.  This  process 
is  repeated  during  several  hours,  when  a  deep  blue  saturated 
solution  of  ammoniacal  copper  oxide  is  obtained.  Neubauer 
recommends  to  precipitate  a  solution  of  copper  sulphate  with 
caustic  soda  in  the  presence  of  ammonium  chloride;  the  pre- 
cipitate so  obtained  is  washed  several  times  by  decantation 
and  finally  on  a  filter.  It  is  then  dissolved  in  the  least  quantity 


ANALYSIS   OF  THE  TEXTILE   FIBRES  465 

of  ammonia  water.     Wiesner  prepares  the  solution  by  digest- 
ing copper  turnings  with  ammonia  water  in  an  open  flask. 

(n)  Ammoniacal  Nickel  Oxide. — Dissolve  5  gms.  of  nickel 
sulphate  in  100  cc.  of  water  and  add  a  solution  of  caustic  soda 
until  the  nickel  hydrate  is  completely  precipitated;  wash  the 
precipitate  well  and  dissolve  in  25  cc.  of  concentrated  ammonia 
and  25  cc.  of  water.  This  solution  dissolves  silk  almost  immedi- 
ately, but  reduces  the  weight  of  vegetable  fibres  only  about 
\  per  cent,  and  of  wool  only  \  per  cent. 

(12)  Caustic  Potash  or  Caustic  Soda. — Dissolve  10  gms.  of 
the  caustic  alkali  in  100  cc.  of  water. 

(13)  Sodium   Nitroprusside. — Dissolve    2   gms.   of   the   salt 
in  100  cc.  of  water. 

(14)  Lead  Acetate. — Dissolve  5  gms.  of  lead  acetate  crystals 
(sugar  of  lead)  in  100  cc.  of  water. 

(15)  Sulphuric  and  Nitric  Acids. — The  commercial  concen- 
trated acids  are  employed. 

(16)  Chlorin  Water. — Water  is  saturated  with  chlorin  gas 
obtained  by  acting  on  pyrolusite   (MnC^)   with  hydrochloric 
acid.     The    solution    should    be    preserved    in    amber-colored 
bottles. 

(17)  I odin  Solution. — Dissolve  3  gms.  of  potassium  iodide 
in  60  cc.  of  water,  and  add  i  gm.  of  iodin.     Dilute  this  solution, 
before  using,  with  10  parts  of  water.     When  the  reaction  is 
employed  in  connection  with  sulphuric  acid,  the  latter  consists 
of  3  parts  of  concentrated  sulphuric  acid,  i  part  of  water,  and 
3  parts  of  glycerol.     The  glycerol  has  the  effect  of  preventing 
injury  to  the  fibres,  and  at  the  same  time  brings  out  certain 
details  of  the  structure  when  the  fibres  have  previously  absorbed 
the  iodin.     The  fibres  are  moistened  first  with  the  iodin  solu- 
tion and  then  with  the  sulphuric  acid  solution. 

The  reliability  of  this  latter  test  depends  very  largely  on  the 
method  of  manipulation.  The  most  important  detail  is  probably 
the  concentration  of  the  acid  used.  After  the  fibres  have  been 
moistened  with  the  iodin  solution  excess  of  the  latter  should 
be  removed  by  pressing  between  blotting  paper,  so  that  only 
that  portion  of  the  solution  absorbed  by  the  fibres  remains. 


466  THE  TEXTILE  FIBRES 

This  is  important,  for  if  the  iodin  solution  remains  between 
the  fibres  the  test  will  be  indecisive.  It  is  also  important  that 
the  individual  fibres  be  separated  from  each  other  so  that  the 
reagents  may  act  uniformly.  If  the  acid  is  too  concentrated 
most  of  the  fibres  assume  a  blue  color,  swell  up  and  finally  dis- 
solve; whereas  if  the  acid  is  too  weak,  all  the  fibres  exhibit  a 
reddish  coloration.  In  carrying  out  the  test,  the  fibres  should 
first  be  boiled  with  potash,  washed,  spread  out  on  glass  slides, 
dried;  then  treated  with  the  ruby  red  solution  of  iodin,  again 
dried,  and  finally  mounted  in  the  sulphuric  acid  solution. 

(18)  Picric  Acid  Solution. — Dissolve  0.5  gm.  of  picric  acid 
in  100  cc.  of  water. 

3.  Distinction  between  Animal  and  Vegetable  Fibres. — The 
simplest  and  most  ready  test  for  this  purpose,  when  the  fibres 
can  be  separated  from  each  other,  is  to  burn  a  sample  of  the 
material.  The  animal  fibres  (wool  and  silk)  will  emit  a  strong 
empyreumatic  odor  of  burning  feathers,  whereas  the  vegetable 
fibres  (cotton,  linen,  etc.)  will  give  off  no  such  disagreeable 
odor,  but  only  pungent  and  somewhat  acrid  fumes  similar  to 
those  from  burning  paper.  In  cases  where  animal  and  vege- 
table fibres  are  mixed  together  and  cannot  readily  be  separated, 
the  burning  test,  of  course,  fails  for  the  detection  of  the  vegetable 
fibre,  though  the  presence  of  the  animal  fibre  will  be  made 
evident. 

A  delicate  reaction  *  for  detecting  the  presence  of  vegetable 
fibres  in  wool  is  the  following:  The  sample  of  material  under 
examination  is  well  boiled  with  water  to  remove  any  finishing 
materials  that  might  be  present  and  interfere  with  the  reaction. 
Then  a  small  portion  of  the  sample  is  put  in  a  test-tube  with  i 
cc.  of  water  and  2  drops  of  an  alcoholic  solution  of  alpha-naphthol 
and  about  i  cc.  of  concentrated  sulphuric  acid.  If  vegetable 
fibres  are  present,  they  will  be  dissolved  and  the  liquid  will 
acquire  a  deep  violet  color  when  shaken;  the  animal  fibres  only 
give  a  yellow  to  reddish  brown  coloration  but  no  violet  tint. 
If  thymol  is  used  instead  of  alpha-naphthol,  a  beautiful  red 
coloration  will  be  produced  in  the  presence  of  vegetable  fibres. 

*  Molisch,  Dingl.  Polyt.  Jour.,  1886,  vol.  261,  p.  135. 


ANALYSIS  OF  THE   TEXTILE  FIBRES 


467 


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468  THE  TEXTILE  FIBRES 

Cross  and  Bevan  have  also  devised  a  delicate  test  which  is 
serviceable  for  detecting  the  presence  of  vegetable  fibres  in  fabrics ; 
the  sample  of  the  cloth  is  immersed  in  a  solution  of  ferric  chloride, 
squeezed  and  then  placed  in  a  solution  of  potassium  ferrocyanide, 
when  any  vegetable  fibre  present  will  be  colored  blue. 

Lieberman  gives  a  test  to  distinguish  between  animal  and 
vegetable  fibres  as  follows:  The  fibres  are  boiled  with  a  solution 
of  magenta  which  has  previously  been  decolorized  by  the  addi- 
tion of  just  sufficient  caustic  soda;  then  they  are  well  washed 
and  placed  in  water  slightly  acidulated  with  acetic  acid.  If 
the  fibres  are  of  animal  origin,  they  will  be  colored  a  deep  pink, 
whereas  cotton  and  linen  fibres  will  be  unaffected. 

Both  this  reaction  and  the  one  with  picric  acid  (see  Table 
II)  are  convenient  to  use  when  it  is  desirable  to  render  visible 
the  animal  fibres  in  a  mixed  yarn  or  fabric.  In  case  of  a  mixture 
of  wool  and  silk  fibres,  the  wool  may  readily  be  shown  by  placing 
the  sample  in  a  very  dilute  boiling  solution  of  caustic  soda  con- 
taining a  few  drops  of  lead  acetate  solution.  Any  wool  present 
will  be  turned  brown  by  this  treatment,  due  to  the  formation 
of _ lead  sulphide  from  the  sulphur  which  forms  a  constituent 
of  this  fibre.  Silk  (and  also  cotton  or  other  vegetable  fibre) 
will  not  be  colored.  In  this  test,  of  course,  it  will  be  necessary 
that  the  sample  is  undyed,  or,  at  least,  that  all  coloring  matters 
originally  present  be  completely  removed. 

In  strong,  cold  sulphuric  acid  silk  quickly  turns  yellow  and 
dissolves;  cotton  disintegrates  slowly  without  color;  flax  and 
hemp  make  a  black  mixture,  and  wool  is  scarcely  affected. 
Both  silk  and  wool  turn  yellow  and  are  soluble  in  nitric  acid, 
the  first  more  speedily,  while  vegetable  fibres  are  slightly 
affected.* 

Behrens  furnishes  the  following  color  test  to  distinguish 
the  several  important  fibres.  It  depends  on  the  relative  reac- 
tions of  these  fibres  with  solutions  of  malachite  green  and  benzo- 
purpurin,  and  is  carried  out  as  follows:  The  mixture  of  fibres 
is  dyed  for  fifteen  minutes  in  a  warm  solution  of  malachite 

*  Seaman,  On  the  Identification  of  Fibres. 


ANALYSIS  OF  THE  TEXTILE   FIBRES  469 

green,  then  washed  until  no  more  color  is  extracted.  It  is 
then  steeped  for  twenty  minutes  in  a  cold  solution  of  benzo- 
purpurin,  and  thoroughly  washed  again.  The  following  results 
will  appear: 

(a)  Silk,  wool,  and  jute  (or  other  strongly  lignified  vegetable 
fibre)  will  be  colored  green.* 

(b)  Hemp   and    Manila   hemp  (or   other    slightly   lignified 
vegetable  fibre)  will  be  colored  dirty  grayish  brown  (mud  color). 

(c)  Cotton  and  linen  will  be  colored  red.t 

An  interesting  qualitative  test  to  distinguish  silk  from  wool 
and  vegetable  fibres  is  the  following  given  by  Lecomte:|  A 
small  portion  of  the  fabric  to  be  examined  is  soaked  in  dilute 
nitric  acid  (100  grams  per  litre)  and  then  treated  gradually 
with  constant  stirring  during  three  minutes  with  30  cc.  of  sodium 
nitrite  solution  (50  grams  per  litre).  After  ten  minutes  the 
fabric  is  well  washed  and  cut  into  two  equal  portions.  The 
first  of  these  is  treated  for  one  hour  with  40  cc.  of  a  cold  solution 
of  sodium  plumbite  and  sodium  naphtholate.  This  solution 
is  prepared  by  dissolving  50  grams  of  sodium  hydrate  in  500 
cc.  of  water,  and  gradually  adding  25  grams  of  lead  sub-acetate 
dissolved  in  300  cc.  of  water.  When  the  resulting  solution  is 
clear  5  gms.  of  beta-naphthol  are  added  and  the  solution  diluted 
to  i  litre.  The  second  portion  of  the  fabric  is  treated  with  40 
cc.  of  a  solution  containing  50  grams  of  sodium  hydrate,  25  gms. 
of  lead  sub-acetate  and  2  gms.  of  resorcin  per  litre.  After  treat- 
ment for  one  hour  both  portions  are  washed  for  fifteen  minutes 
in  water,  then  soaked  in  dilute  hydrochloric  acid  (5  gms.  per 
litre)  again  washed  thoroughly,  then  pressed  between  filter-paper 
and  finally  dried  in  the  dark.  When  examined  under  the 
microscope  the  silk  fibres  will  appear  of  a  reddish  color,  the 
wool  fibres  will  be  black,  and  the  vegetable  fibres  colorless. 

Allen  §  summarizes  in  Table  III  the  reactions  to  distinguish 
silk  qualitatively  from  other  fibres. 

*  The  silk  will  be  dyed  a  light  green  and  the  wool  and  jute  a  dark  green. 
t  The  cotton  will  show  a  light  red  color  while  the  linen  will  be  dark  red. 
t  Jour.  Pharm.  Chem.,  1906,  p.  447. 
§Commer.  Org.  Anal.,  vol.  4,  p.  518. 


470 


THE  TEXTILE   FIBRES 
TABLE   III. 


Test. 

Silk,  Wool,  Fur,  or  Hair. 

Cotton  or  Linen. 

Heated  in  a  small  test- 
tube 

Brittle,  carbonaceous  residue, 
and  odor  of  burnt  feathers. 
Gases  and  condensed  mois- 
ture alkaline  to  litmus 

Charring  and  smell  of 
burning  wood.  Gases 
and  condensed  mois- 
ture acid  to  litmus 

Boiled  on  a  saturated  aque- 
ous  solution   of   picric 
acid  and  rinsed  in  water 

Dyed  yellow 

Unchanged 

Boiled  with  Millon's  rea- 
gent 

Red  coloration 

No  change  of  color 

Treated  with  cold  nitric 
acid  (1.2  sp.gr.) 

Colored  yellow 

No  change  of  color 

Moistened  with  dilute  hy- 
drochloric acid  and 
dried  at  100°  C. 

Unchanged 

Becomes  rotten 

Heated  to  boiling  with  hy- 
drochloric acid 

Silk. 

Wool,  Fur,  or 
Hair. 

Mostly  undissolved 

Dissolved 

Swells,  without 
at  once  dis- 
solving 

Boiled  with  a  cone,  solu- 
tion of  basic  zinc  chlo- 
ride 

Dissolved 

Unchanged 

Unchanged 

Treated  with  cold  Schweit- 
zer's reagent 

Dissolved;  not 
precipitated 
by    addition 
of  salts 

Undissolved; 
dissolves   on 
heating 

Dissolved;  solution 
precipitated  by  addi- 
tion of  salts 

Treated  in  the  cold  with 
io^>er  cent  caustic  soda 

Undissolved 

Dissolved 

Undissolved 

Boiled  with  a  2  per  cent 
solution  of  caustic  soda 

Dissolved;  so- 
lution    not 
darkened  by 
lead  acetate; 
negative    re- 
action   with 
sodium  nitro- 
prusside 

Dissolved;  so- 
lution   gives 
black    or 
brown     pre- 
cipitate with 
lead  acetate 
and  violet 
color  with 
sodium  nitro- 
prusside 

Unchanged 

• 

Behavior  with  Molisch's 
test* 

Dissolved, 
with  little 
coloration 

Undissolved, 
with  yellow 
or  brown  col- 
oration 

Dissolved,    with    deep 
violet  color 

*  See  p.  466. 


ANALYSIS  OF  THE  TEXTILE  FIBRES 


471 


4.  Analytical  Reactions  of  Vegetable  Fibres. — The  follow- 
ing analytical  table  showing  the  reactions  of  the  more  important 
vegetable  fibres  is  given  by  Dodge:* 

TABLE  IV. 


Fibre. 

lodin  and 
Zinc  Chlor- 
ide. 

lodin  and 
Sulphuric 
Acid. 

Cupram- 
monium. 

Anilin 
Sulphate. 

Phloro- 
glucinol. 

Cotton 

Violet 

Blue 

Blue  solu- 

Flax    
Hemp  

do. 
do. 

do. 
do. 

tion 
do. 
do. 

Pale  yellow 

Violet  red 

Jute 

Brown  yel- 

Green blue 

do 

Golden 

Deep  red 

Ramie 

low 
Dull  violet 

Dull  blue 

do. 

yellow 

Manila  hemp  
New  Zealand  flax.  .  .  . 
Aloe 

Yellow  to 
violet 
Golden 
yellow 
Yellow  to 

Green  blue 
Yellow 

Bluish 
Swells- 

Yellow 
Yellowish 
do 

Red 
Pale  red 
Pink 

Cocoa  

brown 
do. 

bluish 

Bright  yel- 

Purplish 

low 

The  solution  of  iodin  and  zinc  chloride  is  prepared  by  taking 
loo  parts  of  zinc  chloride  solution  of  1.8  sp.gr.,  adding  12 
parts  of  water  and  6  parts  of  potassium  iodide,  then  add  iodin 
until  vapors  of  the  latter  begin  to  form.  The  brown  liquid 
thus  obtained  should  be  preserved  away  from  light.  The 
cuprammonium  solution  is  made  by  adding  sodium  carbonate 
to  a  solution  of  copper  sulphate,  whereby  a  mixed  precipitate 
of  copper  hydrate  and  carbonate  is  obtained.  This  is  well 
washed,  and  treated  with  just  sufficient  ammonia  (of  0.91  sp.gr.) 
to  dissolve  it.  The  solution  should  be  well  shaken  and  filtered 
before  using.  The  anilin  sulphate  is  used  as  a  i  per  cent  solu- 
tion; this  reagent  colors  cells  of  woody  fibre  pale  to  deep  yellow 
in  proportion  to  the  amount  of  woody  matter  present.  The 
phloroglucinol  reagent  is  applied  as  follows:  first  a  drop  or  two 


*  Useful  Fibre  Plants,  Bulletin  No.  9  of  U.  S.  Dept.  of  Agriculture. 


472  THE  TEXTILE  FIBRES 

of  a  5  per  cent  solution  of  phloroglucinol  in  95  per  cent  alcohol 
is  applied  to  the  fibre  under  examination,  and  this  is  followed  by 
the  addition  of  a  couple  of  drops  of  strong  hydrochloric  acid. 
Lignified  cells  will  be  stained  red,  while  those  not  lignified  will 
remain  colorless.  A  similar  solution  of  anilin  hydrochloride 
may  be  substituted  for  the  phloroglucinol,  in  which  case  the 
lignified  tissue  will  be  stained  yellow  instead  of  red.  The  iodin 
and  sulphuric  acid  is  applied  in  a  manner  similar  to  that  described 
on  page  465. 

In  an  examination  of  a  sample  the  fibres  should  be  separated 
into  their  ultimate  cells  by  soaking  in  caustic  alkali,  then  rubbing 
between  the  fingers,  or  teasing  out  with  needles.  If  the  separa- 
tion of  the  cells  is  difficult  by  this  means  recourse  must  be  had 
to  boiling  the  fibre  in  a  10  per  cent  solution  of  caustic  soda  or 
Labarraque's  solution  (sodium  hypochlorite),  and  then  fraying 
the  fibre  apart  by  rubbing  in  a  mortar.  After  the  fibre  has  been 
divided  into  its  ultimate  cells,  they  should  be  spread  out  on  a 
slide  moistened  with  glycerol;  this  will  lessen  the  tendency  of 
the  cells  to  curl  up.  A  cover-glass  is  then  laid  on,  and  the 
microscopical  examination  is  made.  In  order  to  make  an 
examination  of  the  section  of  the  fibre  to  determine  the  diameter 
of  the  cells,  the  following  method  is  recommended :  An  imbedding 
mass  Is  made  by  dissolving  70  gms.  of  clean  gum  arabic  in  an 
equal  weight  of  distilled  water ;  then  4  gms.  of  isinglass  (gelatin) 
are  digested  in  16  cc.  of  cold  water  till  swollen,  and  heated  to 
complete  solution.  One-half  of  this  latter  solution  is  strained 
through  a  piece  of  fine  muslin  (the  rest  is  discarded)  and  mixed 
with  the  solution  of  gum  arabic;  10  to  12  cc.  of  glycerol  are 
added,  the  whole  is  well  mixed  and  warmed.  It  is  best  pre- 
served in  small  bottles  containing  a  fragment  of  camphor.  On 
cooling  the  mixture  solidifies,  but  when  it  is  to  be  used  the  bottle 
is  wanned,  a  small  bundle  of  fibres  for  examination  are  tied 
together  and  saturated  with  the  glue,  drawing  the  fibres  out 
carefully  till  they  are  straight  and  parallel.  The  bundle  is 
then  hung  up  and  dried  for  twelve  hours,  after  which  it  will 
be  firm  enough  to  cut  with  a  microtome.  The  slices  thus 


ANALYSIS  OF  THE  TEXTILE  FIBRES  473 

obtained  are  placed  on  a  slide,  and  moistened  with  the  iodin 
solution;  this  dissolves  the  glue,  which  is  absorbed  by  strips  of 
blotting-paper  and  thus  removed.  With  soft  fibres  that  are 
easily  cut,  a  section  may  be  more  simply  obtained  by  soaking 
in  melted  paraffin,  and,  after  cooling,  cutting  on  the  microtome. 
The  wax  may  be  removed  from  the  section  by  dissolving  in 
benzene  or  turpentine. 

Table  V  shows  the  reaction  of  the  various  vegetable  fibres 
with  the  iodin-sulphuric  acid  reagent,  together  with  the  length 
and  diameter  of  the  ultimate  fibre-cells  in  millimetres. 

5.  Distinction  between  Cotton  and  Linen. — As  it  is  often 
desirable  to  discriminate  between  these  two  fibres,  the  follow- 
ing tes-ts,  as  suggested  by  various  authorities,  are  given.  These 
chemical  tests,  however,  are  only  satisfactory  when  the  linen 
is  in  an  unbleached  condition.  Bleached  linen  will  show 
practically  no  difference  from  cotton  in  the  tests,  as  in  both 
cases  the  cellulose  of  the  two  fibres  is  identical  in  its  chemical 
behavior.  The  most  satisfactory  test  to  distinguish  between 
cotton  and  linen  is  to  submit  the  fibres  to  a  microscopical  exami- 
nation. 

(1)  The  fibre  is  burned: 
Cotton — burned  end  tufted. 
Linen — burned  end  rounded. 

(2)  The  fibre  is  immersed  in  concentrated  sulphuric  acid  for 
two  minutes,  washed  well  with  water,  then  with  dilute  ammonia 
water,  and  dried. 

Cotton — forms  a  gelatinous  mass  soluble  in  water. 
Linen — the  fibre  is  unaltered. 

(3)  The  fibre  is  treated  with  an  alcoholic  solution  of  madder 
for  fifteen  minutes: 

Cotton — becomes  bright  yellow  in  color. 
Linen — becomes  dull  orange  yellow  in  color. 

(4)  The  fibre  is  treated  with  an  alcoholic  solution  of  cochineal 
for  fifteen  minutes: 

Cotton — becomes  bright  red  in  color. 
Linen — becomes  violet  red  in  color. 


474 


THE  TEXTILE   FIBKES 


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ANALYSIS  OF  THE  TEXTILE  FIBRES  475 

(5)  The   fibre   is   immersed   in   olive   oil  or   glycerol,  after 
having  been  boiled  in  water  and  well  dried:* 

Cotton — remains  opaque  and  white. 

Linen — becomes  translucent  by  reason  of  the  oil  rising 

by  capillary  action  between  the  individual 

filaments  of  the  fibres. 

(6)  The  fibre  is  treated  with  an  alcoholic  solution  of  rosolic 
acid,  and  then  with  a  concentrated  caustic  soda  solution: 

Cotton — remains  colorless. 

Linen — becomes  rose  red  in  color. 

(7)  The  fibre  is  treated  with  iodin  and  sulphuric  acid  solutions : 
Cotton — becomes  pure  blue  in  color. 

Linen — gives  a  dull  blue  color.     This  test  is  satisfactory 
only  on  unbleached  linen. 

(8)  A  small  portion  of  the  sample  is  boiled  in  a  solution  of 
equal  parts  of  water  and  caustic  potash;  at  the  end  of  two 
minutes  the  sample  is  raised  with  a  glass  rod,  and  placed  between 
several  thicknesses  of  filter-paper  to  remove  the  excess  of  water: 

Cotton — remains  white  or  is  a  pale,  clear  yellow  in  color. 
Linen — becomes    dark    yellow    in    color.     This   test  is 
adapted  only  for  white  goods. 

(9)  Kuhlmann  recommends  the  use  of  a  cold  concentrated 
solution  of  caustic  potash  (sp.  gr.  1.6).     This  causes  unbleached 
cotton  to  shrink  and  curl  up,  and  to  become  gray  or  dirty  white 
in  color;   whereas  unbleached  linen  shrinks  more  than  cotton, 
and  acquires  a  yellowish  orange  color. 

(10)  The  fibres  are  boiled  in  water,  dried,  immersed  in  a 
saturated  solution  of  sugar  and  common  salt,  and  dried.     The 
separate  threads  are  then  ignited: 

Cotton — leaves  a  black-colored  ash. 

Linen — leaves  a  gray-colored  ash. 

(n)  The  fibres  are  treated  with  a  i  per  cent  alcoholic  solu- 
tion of  magenta  (fuchsin),  and  then  washed  with  a  weak  solution 
of  ammonia: 

*  In  this  test  the  fibres  after  saturation  with  oil  should  be  well  pressed  between 
white  filter-paper  to  remove  all  excess  of  the  liquid.  This  test  is  of  doubtful  value 
and  is  not  to  be  recommended  as  at  all  decisive. 


476  THE  TEXTILE  FIBRES 

Cotton — at  first  stained  a  rose  color  which  is  washed  out 

by  the  ammonia. 
Linen — the  rose  color  is  permanent. 

(12)  Herzog*  recommends  the  following  test  to  distinguish 
between  cotton  and  linen  in  a  woven  fabric:  A  small  piece  of 
the  cloth  is  cut  out  and  the  edges  are  fringed.     The  sample 
is  then  steeped  for  a  few  minutes  in  a  lukewarm  alcoholic  solu- 
tion of  cyanin;   it  is  then  washed  with  water  and  treated  with 
dilute  sulphuric  acid.     By  this   treatment   the  cotton  is   com- 
pletely decolorized,  while  linen  retains  a  distinct  blue  coloration. 
To  make  the  blue  color  still  more  distinct,  the  material  should 
be  washed  free  from  acid  and  placed  in  ammonia.     The  colora- 
tion is  said  to  be  due  to  the  presence   on  the  linen  fibre  of 
fragments  of  epidermis  which  readily  absorbs  the  dyestuff. 

(13)  In  Behren's  method  of  distinguishing  cotton  from  linen 
in  fabrics,  the  cloth  is  first  carefully  boiled  in  water  and  then  in 
a  dilute  solution  of  soda  ash  to  remove  finishing  compounds. 
The  sample  is  then  heated  in  a  dilute  solution  of  methylene 
blue  until  a  rather  dark  shade  of  blue  is  obtained.     The  samples 
are  then  washed  with  water  until  the  cotton  has  become  almost 
colorless    and    has    acquired    a    greenish    tone.     Under    these 
conditions  linen  will  remain  a  dark  blue  color.     Zetzsche  rec- 
ommends this  test  as  quite  satisfactory. 

6.  Distinction  between  New  Zealand  Flax  (Phormium  tenax) , 
Jute,  Hemp,  and  Linen. — The  following  series  of  tests  is 
recommended  to  distinguish  between  the  fibres  in  question: 

(i)  The  material  is  immersed  in  chlorin  water  for  one 
minute,  then  spread  on  a  porcelain  dish,  and  several  drops  of 
ammonia  water  added.  New  Zealand  flax  and  jute  become 
at  first  bright  red  in  color,  which  afterward  changes  to  dark 
brown;  linen  and  hemp  acquire  a  much  lighter  shade,  such  as 
clear  brown,  orange,  or  fawn.  This  method  is  very  good  for 
yarn  or  unbleached  cloth,  and  is  particularly  well  adapted  for 
testing  sail-cloth.  French  hemp  retted  in  stagnant  water  is 
colored  a  much  deeper  shade  than  the  same  kind  of  hemp 
retted  in  running  water;  in  either  case  the  color  is  much  darker 

*  Zeit.f.  Farben-  und  Text.  Ind.,  1905,  p.  n. 


ANALYSIS  OF  THE  TEXTILE  FIBRES  477 

than  that  acquired  by  linen.  For  testing  twine  this  method  is 
said  to  give  excellent  results,  but  in  bleached  material  the 
difference  in  the  shades  produced  is  not  very  marked. 

(2)  To  test  bleached  material,  the  sample  is  immersed  for 
one  hour,   at  36°  C.,  in  nitric  acid  containing  nitrous    oxide. 
New  Zealand  flax  assumes  a  blood  red  color,  while  linen  or  hemp 
is  tinted  pale  yellow  or  rose,  according  to  the  method  by  which 
it  was  originally  retted. 

(3)  A  sample  of  the  material  is  heated  in  concentrated  hydro- 
chloric acid.     Hemp  and  linen  will  not  become  colored,  whereas 
New  Zealand  flax  becomes  yellow  at  a  temperature  of  30°  to 
40°  C.,  then  becomes  red,  brown,  and  finally  black. 

(4)  A  sample   of   the  material  is  treated  with  a  solution  of. 
iodic  acid.     Hemp  and  linen  are  not  affected,  but  New  Zealand 
flax  acquires  a  rose-red  color. 

(5)  Jute  is  distinguished  from  New  Zealand  flax  by  soaking 
the  fibres  for  two  to  three  minutes  in  a  solution  of  iodin,  and 
then  rinsing  several  times  in  a  i  per  cent  solution  of  sulphuric 
acid  to  remove  excess  of  iodin.  Jute  acquires  a  characteristic 
reddish  brown  color;  New  Zealand  flax  becomes  clear  yellow 
in  color;  hemp  acquires  a  light  yellow  color,  and  linen  a  blue 
color.  It  will  be  found  best  to  untwist  the  separate  threads 
previous  to  this  treatment.  For  the  preparation  of  the  iodin 
and  sulphuric  acid  solutions,  see  p.  465. 

(6)  Jute  may  be  distinguished  from  flax  and  hemp  by  warm- 
ing in  a  solution  containing  nitric  acid  and  a  little  potassium 
chromate,  then  washing  and  warming  in  a  dilute  solution  of 
soda  ash,  and  washing  again.     The  fibres  are  then  placed  on  a 
microscope   slide,  and  when    the  water  has  evaporated  a  drop 
of  glycerol  is  added.   In  a  short  time  the  characteristic  structure 
of  jute  will  be  easily  observable,  and  under  the  polariscope 
(with  a  dark  field)  the  jute  fibre  will  show  a  uniform  blue  or 
yellow  color,  whereas  linen  and  hemp  will  show  a  play  of  pris- 
matic colors.     Also  with  phloroglucinol  and  hydrochloric  acid, 
jute  is  stained  an  intense  red,  while  linen  remains  uncolored 
and  hemp  acquires  only  a  reddish  tint. 

(7)  To  distinguish  accurately  between  linen  and  hemp  it 


478  THE  TEXTILE  FIBRES 

is  best  to  have  recourse  to  a  microscopical  examination.*  The 
linen  fibres  will  appear  quite  regular  and  with  a  lumen  which  is 
often  reduced  to  a  mere  line,  while  the  hemp  fibre  shows  a  very 
large  lumen,  and  presents  a  rather  irregular  surface.  With  the 
iodin-sulphuric  reagent  hemp  gives  a  green  coloration,  while 
linen  gives  a  blue ;  with  nitric  acid  linen  gives  no  color,  while  hemp 
shows  a  pale  yellow  coloration.  The  ends  of  the  linen  fibres  are 
pointed,  while  those  of  hemp  are  enlarged  and  spatula-shaped. 

According  to  Hanausek  f  linen  and  hemp  may  be  best 
distinguished  microscopically  by  the  use  of  a  solution  of  potas- 
sium bichromate.  The  fibres  of  linen  swell  up  more  rapidly 
than  those  of  hemp,  and  the  dark  patches  formed  on  the  surface 
are  more  pronounced. 

7.  Distinction  between  Manila  Hemp  and  Sisal. — In  their 
characteristics  these  two  fibres  are  very  similar  and  it  is  quite 
difficult   to   distinguish   between    them.     This   may   be   done, 
however,  with  more  or  less  accuracy  by  an  observation  of  the 
color  of  the  ash,  which  in  the  case  of  Manila  hemp  is  grayish 
black,  while  sisal  leaves  a  white  ash. 

8.  Ligneous    Matter  (derived  from  woody  tissue)   may  be 
detected  in  admixture  with  other  fibres  in  the  following  manner: 

(1)  On  exposing  the  moistened  sample  to  the  action  of  chlorin 
or  bromin,  and  then  treating  it  with  a  neutral  solution  of  sodium 
sulphite,  a  purple  color  will  be  produced. 

(2)  If  the  sample  be  moistened  with  an  aqueous  solution  of 
anilin  sulphate,  an  intense  yellow  color  will  be  produced. 

(3)  If  the  sample  be  moistened  with  a  solution  of  phloro- 
glucinol  of  J  per  cent  strength,  and  then  with  hydrochloric  acid, 
an   intense   violet-red    color   will   be   produced.     Solutions    of 
resorcinol,  orcinol,  and  pyrocatechol  act  in  a  similar  manner. 

(4)  Woody  fibre  when  boiled  in  a  solution  of  stannic  chloride 
containing  a  few  drops  of  pyrogallol  gives  a  fine   purple   color, 
which  is  easily  seen  under  a  magnifying-glass. 

9.  Reactions  of  Bast  Fibres. — In  Table  VI,  by  Goodale,  are 
presented  reactions  for  the  principal  bast  fibres. 

*  By  a  determination  of  the  methyl  value  (see  p.  180)  it  is  possible  to  dis- 
tinguish chemically  between  unbleached  flax  and  hemp.  The  phloroglucinol 
test  cannot  be  relied  on  to  distinguish  between  these  two  fibres. 

f  Zeit.  Farb.  Ind.,  1908,  p.  105. 


ANALYSIS  OF  THE  TEXTILE  FIBRES 


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ANALYSIS  OF  THE  TEXTILE  FIBRES  481 

10.  Systematic  Analysis   of  Mixed  Fibres. — Table  VII,  by 
Pinchon  represents  an  attempt  to  give  a  systematic  qualitative 
analysis  of  the  most  important  textile  fibres. 

The  fibre  is  first  treated  with  a  10  per  cent  solution  of  caustic 
potash,  which  causes  any  animal  fibre  to  dissolve,  the  vegetable 
fibres  remaining  insoluble.  If  lead  acetate  solution  be  added  to 
the  fibre  after  treatment  with  caustic  potash,  and  wool  is  present 
it  will  become  dark,  owing  to  the  formation  of  lead  sulphide 
from  the  sulphur  existing  in  the  wool.  If  silk  be  suspected, 
warm  in  concentrated  sulphuric  acid,  which  will  cause  the  silk 
to  darken  rapidly  and  the  wool  more  slowly. 

With  a  due  degree  of  caution,  this  schematic  analysis  may  be 
employed  with  considerable  success,  though  confirmatory  tests 
should  be  applied  to  the  detection  of  each  fibre  indicated.  The 
differentiation  between  the  various  vegetable  fibres  given  is 
especially  difficult. 

11.  Detection  of  Cotton  in  Kapok. — As  kapok  is  a  partly 
lignified  fibre  it  gives  a  yellow  to  yellowish  brown  coloration 
when    treated   with   iodin  and  sulphuric  acid,  whereas  cotton 
gives  a  blue  coloration  with  this  reagent.     This  same  test  also 
serves  to  distinguish  the  general  class  of  Bombax  cottons  from 
ordinary  cotton. 

Kapok  gives  a  reddish  violet  coloration  with  phloroglucinol 
and  hydrochloric  acid,  whereas  cotton  furnishes  only  a  faint 
violet  coloration  with  this  reagent. 

Greshoff,*  gives  the  following  tests  to  distinguish  between 
cotton  and  kapok:  (a)  zinc  chloride  and  iodin  solution  gives  a 
violet-blue  coloration  with  cotton,  but  a  yellow  color  with 
kapok:  (b)  by  immersing  the  fibres  for  one  hour  in  an  alcoholic 
solution  of  magenta  (o.oi  gram  of  magenta  in  30  cc.  of  alcohol 
and  30  cc.  of  water)  cotton  remains  practically  colorless,  whereas 
kapok  is  dyed  a  bright  red.  A  further  test  is  with  Schweitzer's 
reagent;  this  causes  cotton  to  swell  up  and  dissolve,  while 
kapok  is  not  affected.  Greshoff  claims  that  a  quantitative 
estimation  of  cotton  in  kapok  may  be  made  by  distillation  of  the 
material  with  hydrochloric  acid  and  precipitation  of  the  liberated 

*  Chem.  Central,  1908,  p.  647. 


482 


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ANALYSIS  OF  THE  TEXTILE  FIBRES  483 

furfural  by  phloroglucinol.  Kapok  contains  23  to  25  per  cent 
of  pentosans  (furfural  yielding  bodies)  while  cotton  only  has 
about  3  per  cent. 

12.  Microscopical  Comparison  of  Various  Fibres. — Zetzsche, 
in  Table  VIII  (on  p.  484),  gives  comparisons  between  the  prin- 
cipal fibres  as  obtained  by  a  microscopical  examination. 

13.  Identification  of  Artificial  Silks. — In  Table  IX  are  given 
Hassac's  tests  to  identify  the  different  varieties  of  artificial 
silks  or  forms  of  lustra-cellulose,  and  also  the  distinction  between 
these  latter  and  true  silk. 

Collodion  silk  may  be  distinguished  from  viscose  and 
cuprammonium  silks  by  the  fact  that  it  will  always  contain 
at  least  a  trace  of  nitrogen  compound  capable  of  giving  the 
blue  diphenylamine  test  and  the  red  brucine  test  (see  p.  377). 
According  to  Schwalbe  collodion  silk  always  contains  a  small 
amount  of  oxy cellulose  produced  during  the  nitration  process, 
and  hence  may  be  distinguished  from  other  cellulose  silks 
by  the  fact  that  this  oxycellulose  will  cause  a  reduction  of 
Fehling's  solution.  The  test  is  made  by  heating  0.2  gm.  of  the 
artificial  silk  with  2  cc.  of  Fehling's  solution,  when  a  green  color 
is  obtained  with  collodion  silk,  while  with  viscose  or  cupram- 
monium silk  the  liquid  remains  blue.  Schwalbe  also  recommends 
the  use  of  a  solution  of  20  gms.  of  zinc  chloride,  2  gms.  of  potas- 
sium iodide,  and  o.i  gm.  iodin  in  15  cc.  of  water  as  a  reagent  to 
distinguish  viscose  silk  from  cuprammonium  silk.  When  equal 
quantities  of  the  two  silks  are  treated  with  this  reagent  and  then 
washed  with  water,  the  viscose  silk  remains  bluish  green  for 
some  time,  whereas  the  cuprammonium  silk  soon  loses  its  brown 
color.  This  test,  however,  is  not  satisfactory,  as  it  is  difficult 
to  obtain  the  proper  color  reactions.* 

*  Maschner  (Farber.  Zeit.y  1910,  p.  352)  finds  that  even  after  considerable 
practice  a  microscopical  examination  is  not  a  reliable  means  of  distinguishing 
between  different  kinds  of  artificial  silks.  The  most  important  chemical  tests 
are  the  diphenylamine  reaction  recommended  by  Silvern  for  the  detection  of 
collodion  silks,  Schwalbe's  reduction  test  with  Fehling  solution,  for  the  same 
purpose,  and  the  latter's  test  with  a  solution  of  zinc  chlor-iodide  to  distinguish 
between  cuprate  and  viscose  silks.  Maschner  concluded  that  of  these  three  reac- 
tions only  the  first  is  at  all  reliable  as  the  other  two  give  different  results  with 
even  artificial  silks  of  the  same  class.  For  the  same  reason  the  behavior  of 


484 


THE  TEXTILE   FIBRES 


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488  THE  TEXTILE   FIBRES 

Collodion  silk  may  be  distinguished  (though  not  in  a  very 
satisfactory  manner)  from  viscose  and  cuprammonium  silks 
by  the  microscopic  appearance  in  polarized  light  (see  p.  .377) 

Herzog,  in  Table  X  (on  p.  489),  gives  the  microscopical 
characteristics  of  artificial  silks. 

According  to  Beltzer  *  a  solution  of  ruthenium  red  f  (o.oi 
gram  in  10  cc.  of  water)  is  a  useful  microchemical  stain  for  the 
identification  of  artificial  silks.  Collodion  silk  is  stained  a  deep 
red  with  this  reagent,  cuprate  silk  is  scarcely  tinted,  while 
viscose  silk  is  colored  a  deep  pink.  Artificial  silks,  however, 
which  have  been  treated  with  formaldehyde  (for  increasing  their 
resistance  to  water)  are  not  stained  by  ruthenium  red  solution. 

14.  Distinction  between  True  Silk  and  Different  Varieties  of 
Wild  Silk. — True  silk  (from  Bombyx  mori)  rapidly  dissolves 
(one-half  minute)  in  boiling  concentrated  hydrochloric  acid; 
Senegal  silk  (from  Faidherbia)  dissolves  in  a  somewhat  longer 
time,  while  yama-mai,  tussah,  and  cynthia  silks  require  a  much 
longer  time  for  complete  solution.  True  silk  is  also  rather 
easily  soluble  in  strong  caustic  potash  solution,  whereas  the  other 
varieties  of  silk  are  not.  The  most  approved  reagent,  however, 

artificial  silks  toward  dyestuff  solutions  is  not  a  satisfactory  method  of  dis- 
tinction. A  means  to  distinguish  between  the  silks,  however,  is  afforded  by  the 
action  of  concentrated  sulphuric  acid.  The  test  is  as  follows:  0.2  gram  of  the 
silk  to  be  examined  together  with  an  equal  quantity  of  a  standard  artificial  silk 
of  known  make  are  put  in  small  dry  Erlenmeyer  flasks  which  stand  on  white 
paper  and  about  10  c.c.  of  pure  sulphuric  acid  are  poured  over  them.  The  flasks 
are  shaken  to  moisten  thoroughly  the  fibres  and  the  immediate  effect  of  the  acid 
is  observed.  The  flasks  are  then  kept  under  observation  for  about  if  hours. 
Collodion  silk  remains  at  first  quite  colorless  and  only  after  40-60  minutes  does 
the  liquor  assume  a  weak  yellowish  tone.  Cuprate  silk  at  once  takes  on  a  yellow 
or  yellowish  brown  tone  and  the  liquor  becomes  yellowish  brown  after  40-60 
minutes.  Viscose  silk  is  at  once  turned  reddish  brown  by  the  acid  and  the  liquor 
after  40-60  minutes  becomes  a  rusty  brown  color. 

*  See  Monit.  Sclent.,  1911,  p.  633. 

f  Ruthenium  red  has  the  formula  Ru2(OH)_>  C]4(NH3)7+3H,O.  It  is  soluble 
in  water  but  insoluble  in  glycerin  and  alcohol.  In  using  this  stain  as  a  test 
the  object  is  mounted  in  a  drop  of  the  solution,  and  the  degree  of  staining  is 
observed  immediately  and  again  after  twelve  hours.  Ruthenium  red  does  not 
stain  pure  normal  cellulose,  but  does  stain  oxycellulose,  pectins,  gums,  and 
mucilages.  Raw  cotton  is  stained  a  pink,  owing  to  the  presence  of  the  cuticle; 
raw  flax,  ramie,  hemp,  and  jute  are  stained  strongly,  but  irregularly,  owing  to 
pectin  present.  Raw  kapok  fibres  are  practically  not  stained  at  all. 


ANALYSIS   OF  THE  TEXTILE  FIBRES 


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THE  TEXTILE  FIBRES 


for  separating  true  silk  from  the  wild  varieties  is  a  semi-saturated 
solution  of  chromic  acid,  prepared  by  dissolving  chromic  acid  in 
cold  water  to  the  point  of  saturation  and  then  adding  an  equal 
volume  of  water.  True  silk  is  completely  dissolved  on  boiling  in 
this  solution  for  one  minute,  whereas  wild  silk  remains  insoluble. 
Silvern*  gives  the  following  table  showing  the  principal  points 
of  difference  between  ordinary  silk,  tussah  silk,  and  artificial  silk : 


Reagent. 

Chinese  Raw 
Silk. 

Tussah  Silk. 

Artificial 
(Chardonnet) 
Silk. 

Potassium  hydroxide  solu- 

Dissolves on  gent- 

Dissolves    o  n 

Unaltered 

tion,  concentrated 

ly  warming 

boiling 

Potassium    hydroxide,    40 

Acted  on  at  65  °C. 

Swells    up    at 

Insoluble 

per  cent  solution 

Dissolved  at  85° 

75.°  Dissolves 

C. 

at  120°  C. 

Zinc  chloride,  60  per  cent 

Completely    dis- 

Completely 

Dissolves  at  140° 

solution 

solved  at  120  °C. 

dissolved   at 

to  145°  C. 

135°  C. 

Copper  sulphate  ammonia 

Dissolves  i  n  30 

Scarcely     a  t  - 

Not  attacked 

solution      (CuSO,-,       10 

minutes  at  ordi- 

tacked 

even  on  boiling 

grms.;   glycerin,  10  c.c.; 

nary    tempera- 

40 per  cent  NH3,  10  c.c.) 

ture 

Cuprammonium  solution 

Dissolves  with  ex- 

Unattacked 

Unattacked  even 

ception  of  slimy 

on  boiling 

residue 

Fehling's  solution 

Dissolves  readily 

Dissolves     o  n 

Not  attacked 

on  boiling 

boiling 

Millon's  reagent 

Violet  coloration 

Violet    colora- 

No change 

on  boiling 

tion  on  boil- 

ing 

lodin  solution 

Deep  brown  col- 

Faint brown 

Brown  coloration 

oration 

coloration 

changing  to  blue 

Ash 

0-95 

i-i5 

i.  60 

Behavior  at  200°  C.,  and 

Becomes    brown 

Scarcely     a  1  - 

Blue-black  color- 

loss in  weight 

and  friable; 

tered;    11.21 

ation  then  car- 

11.15 percent 

per  cent 

bonization.  Fri- 

able  with  diffi- 

culty;  43  to  65 

per  cent 

Percentage  of  nitrogen 

16.60 

16.79 

0.15 

Percentage  of  water 

7-99 

8.26 

10.37 

Water  absorbed  in  48  hours. 

per  cent 

2.24 

S-oo 

5-24 

*  Farber.  Zeit.,  1900,  p.  283. 


ANALYSIS  OF  THE  TEXTILE  FIBRES  491 

Under  the  microscope  true  silk  can  readily  be  told  from  wild 
silks,  as  the  latter  fibres  are  broad  and  flat,  and  show  very 
distinct  longitudinal  striations,  which  are  absent  in  true  silk. 
Exception  must  perhaps  be  made  with  the  wild  silk  from 
Saturnia  spini,  which  can  scarcely  be  told  from  true  silk  by  a 
microscopical  examination.  With  regard  to  distinguishing 
between  the  different  varieties  of  wild  silks  themselves,  some 
valuable  information  may  be  gained  by  a  determination  of  their 
relative  diameters.  Hohnel  gives  the  following  values  for  the 
greatest  thickness  of  the  different  silks: 

True  silk  (Bombyx  mori] 20  to  25  (x 

Senegal  silk       (Faidherbia  bauhini) 30  to  35  (x 

Ailanthus  silk   (Attacus  cynthid} 40  to  50  [x 

Yama-mai  silk  (Anther -cea  yama-mai) 40  to  50  (x 

Tussah  silk        (Bombyx  selene} 50  to  55  [x 

Tussah  silk        (Bombyx  mylitta) 60  to  65  [x 

According  to  Wiesner  and  Prasch,  the  breadths  of  the  single 
fibres  of  different  silks  are  as  follows: 


Ailanthus  silk 7  to  27,  mostly  14  [X 

Yama-mai  silk 10  to  45,  mostly  23  jx 

Bombyx  mylitta 14  to  75,  mostly  42  (x 

Bombyx  selene .  .- 27  to  41,  mostly  34  jx 

Senegal  silk 12  to  34,  mostly  22  ^ 

True  silk 9  to  21,  mostly  13  (x 


True  silk,  ailanthus  silk,  and  Senegal  silk  do  not  show  any 
cross-marks,  or  only  very  faint  indications  of  such;  whereas 
with  tussah  silk  and  yama-mai  silk  the  cross-marks  are  very 
distinct  and  characteristic. 

The  microscopical  appearance  of  the  end  of  the  fibre  on 
being  torn  apart  also  serves  at  times  as  a  useful  means  of  dis- 
tinguishing the  variety  of  silk;  true  silk,  tussah  silk,  and  yama- 
mai  silk  show  scarcely  any  fraying  at  the  ends;  in  Senegal  silk 
the  fraying  is  very  noticeable  in  almost  every  fibre;  while  in 
ailanthus  silk  about  one-half  of  the  number  of  fibres  show  a 
frayed  end. 


492  THE  TEXTILE  FIBRES 

Besides  the  wild  silks  here  mentioned,  there  are  a  few  others 
of  lesser  importance,  which  for  the  sake  of  completeness  are 
herewith  described. 

1.  Saturnia  polyphemus,   a  North  American  variety,   con- 
sists of  very  flat  fibres,  with  large  air-canals  and  numerous 
structural  filaments  separating  at  the  edge  of  the  fibre;    coarse 
lumps  of  adhering  sericin  are  frequent ;  well-defined  cross-marks 
are  also  frequent.     The  single  fibre  is  about  33  [JL  in  width; 
in  its  polariscopic  appearance  these  fibres  very  much  resemble 
ailanthus  silk. 

2.  Arryndia  ricini,  the  fibres  are  even  more  flattened  than 
the  preceding  and  resemble  a  thin  band  or  ribbon;  large  air- 
canals   are   of  frequent  occurrence;  striations   very  apparent; 
the  sericin  layer  is  in  places  very  thin,  and  sometimes  apparently 
lacking  altogether.     The  double  fibre  is  about  45  to  55  pi  in 
width,  and  4  to  6  ^  thick.     At  the  edge  of  the  fibre  frayed  ends 
of  structural  filaments  are  often   apparent.      Cross-marks  are 
rather   ill-defined,   but    of  frequent    occurrence.     The    sericin 
layer,  though  thin,  is  quite  uniformly  developed. 

3.  Anther  aa  pernyi  has  a  very  flat  fibre,  resembling  a  ribbon ; 
it  does  not  fray  out  at  the  ends,  and  shows  scarcely  any  single 
filaments.     The  double  fibre  measures  60  to  80  [/.  in  width  and 
8  to  10  [L  in  thickness.     Cross-marks  are  rather  few  and  indis- 
tinct.    The  sericin  layer  is  very  thin,  and  in  general  hardly 
noticeable.     Moderately  sized  air-canals  are  present. 

4.  Saturnia  cecropia  is  to  be  found  in  Texas.      The  fibre  is 
also  flat  and  ribbon-like  in  form;  the  double  fibre  measures  60  to 
90  [L  in  width  and  10  to  15  (JL  in  thickness;  air-canals  are  frequent 
and  large,  hence  the  fibre  usually  appears  rather  dark  under  the 
microscope.     The  cross-marks  are  very  distinct,  and  at  such 
points  the  fibre  is  much  broader.     The  fibre  is  usually  much 
frayed  out  and   individual   filaments  are  easily  distinguished. 
The  sericin  layer  is  quite  thin,  but  very  uniform. 

5.  Attacus  lunula  has  fibres  which  are  not  so  flat  as  the  pre- 
ceding.    The  double  fibre  is  25  to  35  ^  in  width  and  12  to  18 
(i  in  thickness.     The  air-canals  are  fine  and  delicate;  and  the 
fibre  shows  but  a  slight  degree  of  fraying.     The  sericin  layer 


ANALYSIS  OF  THE  TEXTILE  FIBRES  493 

is  very  thin  and  finely  granulated  on  the  surface;  in  places  it 
has  the  form  of  irregular  shreds.  The  fibre  as  a  whole  has  a 
brownish  yellow  appearance,  due  to  the  ochre-yellow  color  of 
the  sericin  layer. 

By  the  use  of  the  polariscopic  attachment  to  the  microscope, 
considerable  differences  can  be  observed  in  the  interference 
colors  displayed  by  the  different  varieties  of  silks.  It  is  best 
to  conduct  these  observations  under  a  magnification  of  30 
to  50  diameters;  and  as  the  silk  fibres  are  more  or  less  ovoid 
in.  section,  it  must  be  borne  in  mind  that  the  same  fibre  will  give 
a  different  color  phenomenon,  depending  on  whether  it  is  viewed 
from  the  narrow  side  or  from  the  broad  side.  Hence,  to  obtain 
trustworthy  results,  the  appearance  of  the  same  side  only  of 
the  fibres  should  be  compared.  Also,  the  appearance  of  single 
fibres  only,  and  not  of  crossed  fibres,  should  be  taken. 
Hohnel  gives  the  following  description  of  the  appearance  of  the 
different  silk  fibres  viewed  in  polarized  light,  the  observations 
being  made  with  a  dark  field,  and  under  a  magnification  of  30 
to  50  diameters: 

1.  True  silk:  (a)  broad  side,  very  lustrous,  of  a  bluish  or 
yellowish  opalescent  white;  the  same  color  is  nearly  always  to 
be   found   over   the   entire   breadth;  (b)   narrow  side,   exactly 
similar  to  the  preceding. 

2.  Yama-mai  silk:  (a)  broad  side,  generally  of  a  pure  bluish 
opalescent  white;  also   darker  bluish   to  almost  black   tones; 
nearly  all  of  the  colors  are  brilliant;   (b)  narrow  side,  shows  all 
colors,  very  brilliant  and  contrasted;  darker  and  blackish  tones 
also  occur. 

3.  Tussah  silk  (from  Bombyx  selene):  (a)  broad  side,  shows 
all  colors,  very  brilliant;  thickness  of  the  fibre  very  uneven, 
hence  the  colors  change  through  the  length;  the  thick  parts  are 
dark  blue  and  reddish  violet,  while  the  thinner  parts  are  yellow 
or  orange;  (b)  narrow  side,  shows  bright  red  and  bright  green 
colors,  though  often  but  slightly  visible;  the  colors  form  long 
flecks;  often  only  dark  gray  to  black. 

4.  Tussah   silk    (from   Bombyx  mylitta):  (a)    broad  side,   a 
bluish  opalescent  white  prevailing;  also  brown,  gray,  and  black 


494  THE  TEXTILE  FIBRES 

tones;  the  colors  occur  in  flecks  like  preceding,  though  scarcely 
even  dark  blue,  but  mostly  bright  orange  to  red  or  brown; 
(b)  narrow  side,  color  a  dull  gray  with  bright  red  or  green  flecks; 
the  general  appearance  is  very  similar  to  the  preceding  silk. 

5.  Ailanthus  silk:  (a)  broad  side,  bright  yellow  or  yellow- 
brown  to  gray-brown  colors;  (b)  narrow  side,  nearly  all  colors, 
but  rather  soft  and  not  very  contrasted,  seldom  very  bright, 
but  rather  dull;  short  flecks  of  green,  yellow,  violet,  red,  or 
blue. 

6.  Senegal    silk:  (a)    broad    side,    bright    yellowish    white, 
gray  to  brown,  seldom  bluish  white  in  color;  (b)  narrow  side, 
faint  and  dull  gray,  brown  to  blackish  colors,  seldom  bright 
colors. 

Table  XI  (on  p.  495)  presents  the  microscopical  character- 
istics of  the  most  important  varieties  of  natural  silk.* 

15.  Micro-analytical  Tables  for  Vegetable  Fibres. — The  fol- 
lowing micro-analytical  tables  have  been  adapted  from  Hohnel 
for  the  qualitative  determination  of  vegetable  fibres. 

I.    TABLE    FOR   THOSE   VEGETABLE    FIBRES    BOTANICALLY 
DESIGNATED  AS  HAIR   STRUCTURES. 

1.  (a)  Each  single  fibre  consists  of  a  single  cell (see  4) 

(b)  Each  fibre  consists  of  two  cells,  namely,  a  short,  thick,  underlying 
cell,  and  an  overlying  pointed,  principal  cell.    The  fibres  are  grayish  brown, 
scarcely  0.5  cm.  long;  hard,  wooly,  lifeless,  thin- walled,  but  round-stapled. 
Such  fibres  form  the  thick  upper  coating  on  the  leaves  of  the  Cycadaa  macro- 
zamia  of  New  South  Wales,  and  are  used  as  vegetable  hair  in  upholstery. 

(c)  Each  single  fibre  consists  of  a  series  of  cells,  hence  is  a  cellular 
fibre.     The  cells  are  golden  yellow  to  brown  in  color,  generally  clinging 
together,  and  empty.     The  fibre  as  a  whole  is  highly  lustrous,  but  very 
harsh  and  brittle;  very  thin-walled,   flat,  and  ribbon-shaped;  frequently 
twisted   on  its   axis;  broad  and  0.5  to  2  cms.  long.     Such  fibres  form  the 
thick  coating  on  the  leaves  of  various  ferns  (Cibotium)  in  Asia,  Australia, 
and  Chili.     The  material  is  used  for  upholstery  under  the  name  of  pulu. 

(d)  Each  fibre  consists  of  numerous  cells  growing    side  by  side,  or  of 
several  series  of  such;  forms  the  so-called  tuft     (see  2). 

2.  (a)  Hairs  straight,  stiff;  white  to  dirty  yellow  in  color     (see  3). 

*  Herzog,  Die  Unterscheidung  der  natiirlichen  und  kunsllichen  Seiden.  p.  14. 


ANALYSIS   OF  THE  TEXTILE  FIBRES 


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Variety  of  Silk 
(Single  Fibre). 

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Fagara  Silk, 
Attacus  Cyn- 
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Senegal  Silk, 
Faidherbia 
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S5II[S  PUAV 

496  THE  TEXTILE  FIBRES 

(b)  Hairs  wooly,  tough,  brownish  violet  in  color,  4  to  6  mm.  long; 
consisting  of  long  cotton-like,  flat,  twisted,  spiral  cells,  the  walls  of  which 
are  frequently  thick  and  undulating;  the  contents  of  the  cells  moderately 
abundant,  yellow  to  violet,  and  in  part  colored  red  with  hydrochloric  acid. 
This  fibre  covers  the  small,  egg-shaped,  flattened  fruit  of  the  New  Holland 


FIG.  125. — The  Lesser  Cotton  Grass  (Eriophorum  latifolium).     (After  Dodge.) 

plant  Cryptostemma  calendulaceum.      It  is  used  in  Australia  as  a  stuffing 
material. 

(c)  Hairs,  wooly  harsh,  reddish  yellow  in  color;  the  cells  are  very  thin- 
walled,  colorless,  and  generally  empty;  in  places,  however,  filled  with  a 
homogeneous  reddish  yellow  substance;  where  two  cells  come  together 
side  by  side  there  are  to  be  noticed  round  spots.  The  individual  cells 
are  relatively  broad,  extremely  varied,  and  irregularly  thick;  irregularly 
bent  in  places  and  frequently  knitted  together.  This  fibre  forms  the 


ANALYSIS  OF  THE  TEXTILE  FIBRES  497 

coating  of  a  plant  (Hibiscus  ?)  growing  in  Cuba;  as  employed  for  upholstery 
materials  it  goes  by  the  name  of  Majagua. 

3.  (a)  The  hairs  are  i  to  3  cm.  long,  and  on  the  average  are  under  50 
[L  wide;  they  consist  of  two  layers  of  cells  which  grow  into  one  another. 
The  inner  walls  are  rough;  the  outer  walls  are  thin  and  indented,  hence 


FIG.  126. — Cotton  Grass  (Eriophorum  anguslifolium) .     (After  Dodge.) 

lie  close  against  the  inner  portion;  the  section  walls  are  quite  noticeable 
and  thick;  the  tufts  end  in  2  to  6  pointed,  often  hook-shaped  cells;  the 
end  cells  show  numerous  pores;  weakly  lignified.  This  fibre  consists  of 
the  ripe  fruit  spicula  of  cotton-grass,  Eriophorum  angustifolium,  E.  latifolium, 

etc Cotton-grass  (see  Fig.  125). 

(6)  The  fibres  are  5  mm.  long;  mean  breadth  of  the  tufts  8  to  16  JJL, 
the  widest  being  under  30  y.;  the  tufts  do  not  end  with  sharp-pointed  cells; 
the  section-walls  under  low  magnification  appear  as  little  knots  and  are 


498  THE  TEXTILE  FIBRES 

usually  quite  noticeable.  This  fibre  is  obtained  from  the  small,  lance-like 
fruit  of  the  reed  mace,  Typha  angustifolia,  which  grows  on  a  small  shaft, 
and  carries  the  hairs  on  the  other  end.  It  is  used  for  upholstery  and  other 
filling  material Reed-mace  hair  (see  Fig.  128). 

4.  (a)  The  fibres  are  flat,  wooly,  frequently  twisted  in  a  spiral  manner 

on  their  axes;  not  lignified (see  5). 

(b)  The   fibre   is   generally   cylindrical,    stiff,   not   twisted;  somewhat 
lignified,  hence  colored  red  with  indophenol  or  phloroglucinol (see  6). 

5.  (a)  Fibres  i  to  5  cm.  long;  white  to  yellowish  brown;    12  to  42  n 

thick Cotton  (see  Fig.  1 29). 

(ft)  Fibres  only  9.5  cm.  long;  very  thin;  usually  consisting  of  tufts; 
violet-brown  in  color.     See  above,  under  2  (6) Cryptostemma  hairs. 


FIG.  127. — Fibres  of  Cotton  Grass  or  Vegetable  Silk.     (Xso,)     The  sharp  fractures 
show  the  brittle  nature  of  the  fibre.     (Micrograph  by  author.) 

6.  (a}  The  product  consists  of  grassy  spicula  with  a  hairy  covering;  the 
hairs  are  5  to  8  mm.  long  and  about  10  to  15  [x  wide;  the  thickness  of  the 
wall  of  the  thick,   cylindrical-pointed  hairs  remains  rather  uniform   up 
to  the  point  itself,  hence  the  latter  appears  very  thick;  spots  are  often 
observed.     This  fibre  is   upholstery   material  from  Saccharum  qfficinalc. 

Sugar-cane  hairs. 

(b)  The  product  consists  of  short  white  fibres,  about  8  to  24  ^  in  width, 
and  of  oval,  flat  fruit -shells,  4  mm.  wide  and  5  mm.  long;  the  hairs  are 
broadened  at  the  base,  hence  generally  knife-shaped;  thick- walled,  with 
transverse,  fissure-like  marks;  the  upper  portion  of  the  hair  is  very  thin 
and  rough- walled;  colorless;  the  ends  are  usually  blunt  and  contain  a 
granular  matter;  slightly  lignified,  especially  at  the  base Poplar  cotton. 

(c)  The  product  consists  entirely  of  hairs  and  is  almost  entirely  free 
from  accidental  impurities Vegetable  down  and  silk. 

7.  (a)  The  fibres  have  two  to  five  longitudinal  ridges  on  the  walls,  which 


ANALYSIS   OF  THE  TEXTILE   FIBRES 


499 


are  either  crescent-shaped  or  quite  flat,  running  into  network  at  the  base; 
these  ridges  are  broad  and  difficult  to  discern  in  a  surface  view  of  the  fibre 
yet  sometimes  very  apparent;  the  maximum  thickness  about  35  \L;  white 
or  yellowish  in  color.  These  fibres  are  the  seed-hairs  of  Apocynum  and 
Asdepias Vegetable  silk  (see  Fig.  127). 


FIG.  128. 


FIG.  130. 


FIG.  128. — Reed-mace  Hair.     (X340.)     (Hohnel.)     A,  portion  of  hair;    B,  ripe 

fruit  at/;  A,  hair  around  fruit;  s,  cells;  k,  knotted  structure. 
P"iG.  i2t). — Cotton  Fibres.     (Xi7o.)     Various  cotton  fibres  with  sections  above. 

/,  lumen;  d,  twists;  s,  granulations  on  cuticle.     (After  Hohnel.) 
FIG.  130, — Fibre  of  Strophanlus.     (X3oo.)  a,  longitudinal  view;   b,  cross-section. 
(Micrograph  by  author.) 

(b)  The  fibres  are  without  ridges;  transverse  ridges  frequently  at  the 
base  or  as  a  network.  Maximum  thickness  generally  under  35  JA;  yellowish 
to  brown.  These  fibres  consist  of  the  hairs  which  cover  the  fruit-pods  of 
Bombacea Vegetable  down  (see  13). 


500 


THE  TEXTILE  FIBRES 


8.  (a)  The  hairs  are  3.5  to  4.5  cm.  long,  and  the  largest  are  50  to  60  p 
in  diameter (see  9) . 

(b)  The  fibres  are  1.5  to  4  cm.  long,  and  the  largest  are  35  to  45  [/.  in 
diameter (see  10). 

9.  (a)  The  fibres  are  narrowed  at  the  base,  and  directly  above  are  strongly 
swollen,  and  up  to  100  \JL  in  thickness;  numerous  pores  at  the  base;  the 
fibres  grow  brush-like  on  a  stem,  are  yellowish  and  harsh.     This  is  vegetable 
silk  from  Senegal Stropkantus  (see  Fig.  130). 

(b)  The  fibres  are  white,  firm,  and  tough,  not  harsh;  form  a  hairy  tuft 
or  crown.     This  is  vegetable  silk  from  India.    Beaumontia    grandiflora. 

(see  Fig.  131). 


FIG.  132* 


FIG.  131. — Vegetable  Silk  from  Beaumontia  grandiflora  (Xi7o.)  b,  base  of 
fibre;  s,  pointed  ends;  q,  cross-section;  m,  middl*  portion  of  fibre;  w,  cell- 
wall;  /,  longitudinal  ridges.  (After  Hohnel.) 

FIG.  132. — Vegetable  Silk  from  Asdepias  cornuti.  (X3oo.)  a,  longitudinal  view; 
b,  cross-sections;  r,  thickened  ridges;  w,  cell-wall.  (Micrograph  by  author.) 

(c)  Yellow  rod  fibres,  weak,  stiff,  straight,  and  harsh. 

Calotropis  procera,  Senegal. 

10.    (a)  At  base  of  the  hair  there  are  spots  or  pores (see  n). 

(b)  Spots  or  pores  lacking.     Vegetable  silk  from  Asdepias  cornuti, 
curassavica,*  etc (see  Fig.  132). 


*  This  plant  grows  in  tropical  and  sub-tropical  America,  and  is  also  found  in 
India.  Its  seed-hairs  are  said  to  be  stronger  than  those  of  most  other  varieties 
of  such  fibres. 


ANALYSIS  OF  THE  TEXTILE  FIBRES  501 

11.  (a)  Spots  large;  round  or  oblique;  the  walls  of  the  fibre  are  not 
thicker  at  the  base  than  at  the  upper  portion;  the  ridges  on  the  fibre  are 
remarkably  well  developed,  the  hairs  are  strongly  bent  back  at  the  base. 
Vegetable  silk  from  Calotropis  gigantea. 

(b}  Spots   small,   no   longitudinal   markings;  walls  thicker  than  the 
foregoing  fibre;  ridges  less  noticeable  and  often  apparently  lacking .  (see  12). 

12.  (a)  Hairs  narrowed  at  the  base Hoy  a  viridiflora. 

(b)  Hairs  not  narrowed  at  all,  or  scarcely  so Marsdenia. 

13.  (a)  The  hairs  have  mesh-like  ridges  at  the  base  situated  obliquely, 
or  have  spiral  ridges (see  14) 


FIG.  133. — Vegetable  Down  (Bombax  ceiba).     (X3oo.)     (Micrograph  by  author.) 

(b)  Without  mesh-like  ridges  at  the  base (see  15). 

14.  (a)  Base  broader,  thin-walled,  with  oblique,  mesh-like  ridges  or 
spiral  swellings,  which  often  extend  to  a  considerable  distance.  Points 
very  thin-walled,  gradually  tapering,  not  ended  sharply;  frequently 
containing  a  reddish  brown  homogeneous  granular  substance;  fibre  not 
very  stiff,  usually  notched.  Base  contains  no  marrow.  Vegetable  down 
from  Eriodendron  anfractuosum. 

(b)  Quite  similar,  but  the  ends  are  not  so  tapering;  without  marrow; 
whole  fibre  somewhat  rough- walled.  Vegetable  down  from  Bombax  hepta- 
phyllum. 


502 


THE  TEXTILE  FIBRES 


(c)  Very  similar  to  (a),  but  walls  of  fibre  are  quite  roughened  and  con- 
lain  at  intervals  throughout  its  length  a  granular  marrow;  base  thick- 
walled,  mesh-like  fibrous  ridges,  but  neither  spirally  developed  nor  very 
broad — at  most  only  one-sixth  of  the  width  of  the  fibre;  ends,  as  before, 

(hick-walled.     Vegetable  down,  Ceiba  cotton, 

from  Bombax  ceiba (see  Fig.  133). 

15.  (a)  Raw  fibre,  brown,  rough- walled ; 
walls,  i  to  7  [x  thick;  not  indented;  points 
without  marrow;  stiff  and  very  sharp  at 
end;  base  not  broadened,  often  contains 
granular  matter.  Vegetable  down  from 

Ochroma  lagopus (see  Fig.  134). 

(b)  Raw  fibre,  yellowish,  thin-walled, 
walls  very  uneven  in  thickness;  frequently 
weakly  developed  longitudinal  ridges;  just 
at  the  base  the  wall  is  very  thick.  Vege- 
table down  from  Cochlospermum  gossypium. 

II.  GENERAL  TABLE  FOR  THE  DETER- 
MINATION OF  THE  VEGETABLE 
FIBRES. 

Including  cotton,  as  well  as  the  more 
important  fibres  derived  from  bast  or 
sclerenchymous  tissues. 

A.  Fibres  Colored  Blue,  Violet,   or 
Greenish  with  lodin  and  Sulphuric  Acid. 
(a)  BAST  FIBRES  AND  COTTON.     (Cotton, 
flax,  hemp,  sunn   hemp,  ramie,  Roa  fibre.) 
I.  The   cross-sections    become    blue   or 
violet  with  iodin  and  sulphuric  acid;  show 
no  yellowish  median    layer;    the  lumen  is 
often  filled  with  a  yellowish  marrow. 

i .  Cross-sections:  they  occur  either  singly 
or  in  small  groups;  the  single  sections  do  not  join  over  one  another;  are 
polygonal,  and  have  sharp  edges;  iodin  and  sulphuric  acid  colors  them 
blue  or  violet;  they  show  closely  packed,  delicate  layers;  the  lumen 
appears  as  a  yellow  point. 

Longitudinal  appearance:  with  iodin  and  sulphuric  acid,  quite  blue; 
it  appears  transparent,  quite  uniformly  thick;  smooth  or  delicately  marked ; 
joints  frequent;  indications  of  dark  lines  running  through,  which  -are 
usually  crossed;  enlargements  on  the  fibre,  especially  at  the  joints,  fre- 
quent; the  lumen  appears  as  a  narrow  yellow  line;  the  natural  ends  of 


FIG.  134.  —  Ochroma  lagopus. 
(X34Q.)  (Hohnel.)  m, 
middle  part  of  fibre;  b,  base; 
s,  pointed  end;  /,  lumen;  q, 
cross-section;  w,  cell- wall. 


ANALYSIS  OF  THE  TEXTILE  FIBRES  503 

the  fibres  are  sharply  pointed;  length  4  to  66  mm.,  thickness  15  to  37  ^. 

Linen  or  Flax. 

2.  Cross-sections  single  or  very  few  in  a  group,  loosely  held  together; 
polygonal  or  irregular,  mostly  flat,  very  large;  colored  blue  or  violet  with 
iodin  and  sulphuric  acid;  stratification  not  noticeable;  the  lumen  is  large 
and  irregular;  frequently  filled  with  a  dark  yellow  marrow;  radial  fissures 
frequently  apparent. 

Longitudinal  appearance:  many  of  the  fibres  remarkably  broad;  the 
width  of  a  single  fibre  very  uneven;  smooth  or  striped;  very  often  ruptures 
in  the  wall;  with  iodin  and  sulphuric  acid,  blue  or  violet;  the  lumen 
readily  seen;  very  broad,  often  containing  a  dark  yellow  marrow;  joints 
noticeable;  dark,  transverse  lines  frequent,  often  crossing  each  other; 
the  ends  are  relatively  thick- walled  and  blunt;  length  60  to  250  mm., 
thickness  up  to  80  [JL China  grass,  Ramie. 

3.  Cross-section:  not   many  in   the  groups;    polygonal;    mostly  with 
straight  or  slightly  curved  sides  and  blunt  angles;   the  lumen  is  contracted 
lengthwise  regularly;  frequently  contains  a  yellow  marrow,  many  sections 
are  surrounded  by  a  thin,  greenish  colored  layer;   not  closely  joined  to 
one  another.     The  sections  often  show  very  beautiful  radial  marks  or 
fissures  and  concentric  layers;  the  various  layers  are  colored  differently. 

Longitudinal  appearance,  as  with  China  grass;  proportional  dimensions 
similar , Roa  fibre. 

4.  Cross-sections    always    isolated,    rounded,    various   shapes,  mostly 
kidney-shaped;     with    iodin    and  sulphuric  acid,  blue  or  violet;    lumen 
contracted,  line-shaped,  often  containing  a  yellowish  marrow;  no  stratifica- 
tion. 

Longitudinal  appearance:  fibres  always  separate;  with  iodin  and 
sulphuric  acid,  a  fine  blue;  streaked  and  twisted;  lumen  broad,  distinct, 
frequently  contains  yellowish  marrow;  ends  blunt;  the  entire  fibre  not 
soluble  in  concentrated  sulphuric  acid;  coated  with  a  very  thin  cuticle; 
length  10  to  60  mm.,  breadth  12  to  42  (i Cotton. 

II.  Cross-section  blue  or  violet  with  iodin  and  sulphuric  acid;  poly- 
hedral, rounded  or  irregular;  always  surrounded  by  a  yellow  median 
layer. 

i.  Cross-sections  always  in  groups,  with  angles  more  or  less  rounded 
off,  lying  very  close  to  one  another;  all  of  them  surrounded  by  a  thin, 
yellowish  median  layer;  the  lumen  is  line-shaped,  single  or  forked,  often 
broad,  with  inturning  edges,  without  marrow;  good  concentric  stratification; 
the  different  strata  being  differently  colored. 

Longitudinal  appearance:  with  iodin  and  sulphuric  acid,  blue,  greenish, 
or  dirty  yellow;  fibres  irregular  in  thickness,  frequently  with  appended 
portions  of  yellowish  median  layer;  joints  and  transverse  lines  frequent; 
stripes  very  distinct;  the  lumen  is  not  very  apparent,  but  broader  than 


504 


THE  TEXTILE  FIBRES 


linen;  ends  are  broad,  thick- walled,  and  blunt,  often  branched;  length 
5  to  55  mm.,  breadth  16  to  50  [x Hemp  (see  Fig.  135). 

2.  Cross-sections  in  large  groups,  lying  very  close  together  and  touch- 
ing; very  similar  to  those  of  hemp;  often  crescent-shaped.  Polygonal 
or  oval,  with  lumen  of  varying  size,  frequently  containing  yellowish  marrow; 
lumen  usually  not  line-shaped,  but  irregular;  a  broad  yellow  median 
layer  always  present,  from  which  the  blue  inner  strata  are  easily  distin- 
guished; stratification  very  distinct,  as  with  hemp. 

Longitudinal  appearance,  as  with  hemp,  except  in  dimensions,  which  are : 
length  4  to  12  mm.,  breadth  25  to  50  ^ Sunn  hemp. 

(b)  LEAF  FIBRES.  (With  vascular  tissue;  without  jointed  structure. 
Esparto  and  pineapple  fibre.) 


A 


FIG.  136. 

FIG.  135. — Hemp.     (Xiyo.)     b,  ends  of  fibres;    c,  cross-section;    d,  longitudinal 

view.     (After  Hohnel.) 

FIG.  136 — Esparto  Grass.     (Xi7o.)     s,  short  sclerenchymous  elements;   /,  cells; 
/,  fibres;   h,  hairs;   e,  epidermal  cells.     (After  Hohnel.) 

1.  Cross-sections    in    large,    compact,    often    crescent-shaped    groups; 
very  small;   pale  blue  or  violet  with  iodin  and  sulphuric  acid;   surrounded 
by  a  thick,  shell-like  network  of  median  layer;    rounded  or  polygonal; 
lumen  like  a  point  or  streak;  thick  cuttings  appear  greenish  or  even  yellow ; 
frequently  bundles  of  vascular   tissue  with  one    or  two   rows  of   thick, 
yellow-colored  fibres. 

Longitudinal  appearance:  Fibres  slender,  regular,  very  thick-walled, 
smooth;  lumen  often  invisible,  generally  as  a  fine  line;  ends  are  tapered  with 
needle-like  points;  color  with  iodin  and  sulphuric  acid,  blue,  but  often 
quite  faint;  frequently  present  short,  thick,  stiff,  completely  lignified  fibres 
from  vascular  tissue;  length  5  mm.,  breadth  6  jx Pineapple  fibre. 

2.  Cross-sections  in  groups;    with  iodin  and  sulphuric  acid,   mostly 


ANALYSIS  OF  THE  TEXTILE  FIBRES  505 

blue,  though  also  yellow;  often  with  pronounced  stratification;  the  outer 
strata  frequently  yellow,  while  the  inner  are  blue;  rounded  or  oval,  seldom 
straight-sided;  lumen  like  a  point. 

Longitudinal  appearance:  the  fibres  are  short;  blue  with  iodin  and 
sulphuric  acid;  thin,  very  firm,  smooth,  uniform  in  breadth;  lumen  yellow, 
line-shaped ;  ends  are  seldom  pointed,  mostly  blunt  or  chiselled  off,  or  forked ; 
length  1.5  mm.,  breadth  12  [x Esparto  (see  Fig.  136). 

B.  Fibres  Colored  Yellow  with  Iodin  and  Sulphuric  Acid. 

(a)  DICOTYLEDONOUS  FIBRES.  (Without  vascular  bundles;  lumen 
showing  remarkable  contractions.  Including  jute,  Abelmoschus,  Gambo 
hemp,  Urena,  and  Manila  hemp;  the  latter  sometimes  shows  vascular 
tissue.) 

I.  Cross-sections  in  groups;    polygonal  and  straight-lined,  with  sharp 
angles;   lumen  round  or  oval,  smooth,  and  without  marrow,  cross-sections 
with  narrow  median  layers  showing  the  same  color  as  the  inner  strata 
with  iodin  and  sulphuric  acid;  lengthwise  appearance  shows  the  lumen  with 
contractions. 

1.  Cross-sections   polygonal,    straight-lined;  lumen,    in   general,    large, 
round,  or  oval. 

Longitudinal  appearance:  fibres  smooth,  without  joints  or  stripes; 
lumen  distinctly  visible;  broad;  with  contractions;  the  ends  always  blunt 
and  moderately  thick;  ends  have  wide  lumen;  length  1.5  to  5  mm.,  breadth 
20  to  25  [JL Jute. 

2.  Cross-sections  in  general  somewhat  smaller  than  jute;  sides  straight, 
with  sharp  angles;  lumen  frequently  like  a  point  or  line,  oval,  occasionally 
pointed;  not  so  large  as  with  jute. 

Longitudinal  appearance:  fibres  quite  even  in  thickness,  smooth,  with 
occasional  joints  or  stripes;  lumen  narrow,  irregular  in  thickness,  con- 
tractions frequent;  the  ends  are  broad,  blunt,  frequently  thickened; 
length  i  to  1.6  mm.,  breadth  8  to  20  ^.  .Pseudo-jute  or  Musk  mallow  of 
Abelmoschus. 

II.  Cross-sections  in  groups,  lying  close  together;  polygonal,  with  sharp 
lines  and  sharp  or  rounded  angles;    lumen  without  marrow;    the  median 
layer  is  broad,  and  with  iodin  and  sulphuric  acid  is  colored  perceptibly 
darker  than  the  inner  layer  of  cell- wall;  the  lumen  in  places  is  completely 
lacking. 

i .  Cross-sections  more  or  less  polygonal,  with  sharp  or  slightly  rounded 
angles;  the  lumen  is  small,  becoming  broader  and  more  oval  as  the  section 
is  more  rounded;  the  median  layer  is  broad,  and  is  colored  considerably 
darker  than  the  cell- wall  with  iodin  and  sulphuric  acid;  stratification 
occasional  and  indistinct. 

Longitudinal  appearance:  the  fibres  vary  much  in  thickness;  lumen 
generally  narrow,  with  decided  contractions,  and  in  some  parts  totally 


503 


THE  TEXTILE   FIBRES 


absent;    the  broader  fibres  often  striped;    ends  are  blunt  and  generally 
thickened;  length  2  to  6  mm.,  breadth  14  to  33  [x Gambo  hemp. 

2.  Cross-sections  always  in  groups;  small,  polygonal,  with  sharp  angles; 
lumen  very  small,  appearing  as  a  point  or  a  short  line. 

Longitudinal  appearance:  occasionally  jointed  or  striped;  lumen  with 
decided  contractions,  in  some  places  altogether  lacking;  ends  blunt  and 
sometimes  thickened;  length  i.i  to  3.2  mm.,  breadth  9  to  24  [x. 

Pseudo-jute  from  Urena  sinuata  (see  Fig.  137). 

(ft)  MONOCOTYLEDONOUS  FIBRES.  (Occurring  as  vascular  bundles 
together  with  bast;  the  lumen  exhibits  no  contractions;  in  Manila  hemp 


FIG.  137. — Pseudo-jute  (Urena  sinuata).  (X34O.)  (Hb'hnel.)  /,  longitudinal 
view;  v,  interruption  of  lumen;  e,  end  with  thick  wall;  q,  cross-section;  m, 
median  layer;  L,  small  lumen. 

vascular  bundles  often  lacking.  Includes  New  Zealand  flax,  Manila  hemp 
Sansevieria  or  bowstring  hemp.  Pita  hemp,  and  Yucca  fibre.) 

I.  Cross-sections  generally  rounded,  occasionally  polygonal;  the 
lumen  is  always  rounded,  without  contractions  longitudinally;  median 
layer  indistinct,  or  only  as  a  narrow  line;  vascular  tissue  small  in  amount, 
or  altogether  lacking. 

i.  Cross-sections  small,  generally  rounded,  lying  loosely  separated; 
very  rounded  angles;  lumen  small,  round,  or  oval,  without  marrow. 

Longitudinal  appearance:  the  fibres  are  stiff  and  thin;  the  lumen  is  small 
but  very  distinct,  and  uniform  in  width;  the  ends  are  pointed;  no  markings 
and  no  joints;  length  5  to  15  mm.,  breadth  10  to  20  ix. .  .New  Zealand  flax. 


ANALYSIS  OF  THE  TEXTILE   FIBRES 


507 


2.  Cross-sections  polygonal,  with  rounded  angles,  in  loosely  adherent 
groups;  lumen  large  and  round,  often  containing  yellow  marrow. 

Longitudinal  appearance:  fibres  uniform  in  diameter;  walls  thinner 
than  those  of  New  Zealand  flax;  lumen  large  and  distinct;  ends  pointed 
or  slightly  rounded;  silicious  stegmata  adhering  to  the  fibre-bundles  and 
to  be  found  in  the  ash  as  bead-like  strings,  insoluble  in  hydrochloric  acid; 
length  3  to  12  mm.,  diameter  16  to  32  jx Manila  hemp. 

II.  Cross-sections  polygonal;  lumen  large  and  polygonal,  with  angles 
quite  sharp;  median  layer  lacking  or  only  in  the  form  of  a  thin  line. 

i.  Cross-sections  distinctly  polygonal,  often  with  blunt  angles,  lying 
compactly  together;  lumen  large  and  polygonal,  with  sharp  angles;  no 
stratification  in  cell-wall. 


FIG.  138. — Yucca  Fibre.     (X4oo.)     A,  longitudinal  view;    B,  cross-section;    m, 
median  layer;  /,  transverse  markings.     (Micrograph  by  author.) 

Longitudinal  appearance:  fibres  thin  and  smooth;  lumen  large  and 
distinct;  ends  pointed;  length  1.5  to  6  mm.,  diameter  15  to  26  [A. 

Sansemeria  fibre. 

2.  Cross-sections  polygonal,  not  many  sections  to  a  group,  but  lying 
compactly   together;     angles   slightly   rounded;     lumen   not   very   large, 
polygonal,  often  having  blunt  angles;    besides  the   bast-fibre  sections  are 
to  be  noticed  some  vascular  bundles  in  the  form  of  large  spirals. 

Longitudinal  appearance:  fibres  uniform  in  diameter;  lumen  not  very 
large,  but  uniform;  no  structure;  ends  pointed  and  sometimes  blunt; 
length  1.3  to  3.7  mm.,  diameter  15  to  24  [x Aloe  hemp. 

3.  Cross-sections  polygonal,  with  straight  lines;    angles  sharp,  though 
sometimes   blunt;     sections   lie   compactly    together;     lumen   large   and 
polygonal,  though  angles  not  so  sharp. 

Longitudinal  appearance:  fibres  stiff,  and  often  very  wide  toward  the 
middle;  lumen  large;  ends  broad,  thickened,  and  often  forked;  large, 
shining  crystals  to  be  found  in  the  ash,  which  are  derived  from  the  chisel- 
shaped  crystals  of  calcium  oxalate  clinging  to  the  outside  of  the  fibre; 


508  THE  TEXTILE  FIBRES 

these  crystals  are  often  J  mm.  in  length;  length  of  fibre  i  to  4  mm.,  diameter 
20  to  32  [x Pita  hemp. 

III.  Cross-sections  polygonal  and  small,  sides  straight,  with  very 
sharp  angles;  lumen  small,  usually  as  a  point  or  line-shaped;  sections 
lie  compactly  together  and  are  surrounded  by  a  thick,  distinct  median 
layer. 

i.  Cross-sections  as  above. 

Longitudinal  appearance:  fibres  very  narrow;  lumen  also  very  narrow; 
longitudinal  ridges  frequent;  ends  usually  sharp-pointed;  length  0.5  to 
6  mm.,  diameter  10  to  29  yi , Yucca  fibre  (see  Fig.  138). 


III.  ANALYTICAL  REVIEW  OF  THE  CHIEF  VEGETABLE  FIBRES. 

1.  Those  occurring  as  thick,  fibrous  bundles,  also  with  vascular  tissue 
(monocotyledonous  fibres) (see  2). 

Vascular  tissue  absent;  sections  and  fibres  always  single;  round  or 
kidney-shaped  by  being  pressed  together;  fibres  with  a  thin  external 
cuticle  insoluble  in  concentrated  sulphuric  acid,  and  not  swelling  (vegetable 
hairs) (see  7). 

Vascular  tissue  absent;  the  fibres  are  bundles  of  bast  filaments;  sec- 
tions occurring  two  or  more  together  (mostly  true  dicotyledonous  fibres) 

(see  13). 

2.  Lumen   very   narrow,   line-shaped,    much   thinner   than   the   wall. 

(see  3). 

Lumen  in  thickest  fibres  almost  as  wide,  or  even  wider,  than  the  wall; 
completely  lignified (see  4) . 

3.  Sections  polygonal,  sides  straight,  with  sharp  angles;    completely 
lignified;  diameter  10  to  20  ^ Yucca    fibre  (see  Fig.  138). 

Sections  rounded  to  polygonal;  often  flattened  or  egg-shaped;  the 
inner  strata  at  least  not  lignified;  diameter  4  to  8  [A Pineapple  fibre. 

4.  Thick,   strongly  silicified   stegmata   occurring  at  intervals  on   the 
fibre-bundles  in  short  to  long  rows,  sometimes  but  few;    these  are  four- 
cornered,  have  serrated  edges,  and  show  a    round,   bright,   transparent 
place  in  the  middle ;  they  are  easily  seen  after  the  fibre  has  been  macerated 
with  chromic  acid,  and  are  about  30  ^   in  length;  in  the  ash  of  fibres  pre- 
viously treated  with  nitric  acid,  they  appear  in  the  form  of  pearly  strings, 
often  quite  long,  and  insoluble  in  hydrochloric  acid ;  they  are  joined  together 
lengthwise;    the  fibres  are  thick- walled,  with  fissure-like  pores;    3  to  12 
mm.  long;  the  fibre-bundles  are  yellowish  and  lustrous Manila  hemp. 

Stegmata  present,  sometimes  in  small,  sometimes  in  large  quantities; 
they  are  lens-shaped,  small  (about  15  \L  wide),  and  are  fastened  to  the 
exterior  fibres  of  the  bundles  by  serrated  edges;  in  the  ash  of  the  fibre  they 


ANALYSIS  OF  THE  TEXTILE  FIBRES  509 

melt  together  in  the  form  of  indistinct  globules;  in  the  ash  of  fibres  pre- 
viously boiled  in  nitric  acid  they  appear  as  yeast-cells,  joined  together  in 
round  skeletons  of  silica;  the  fibres  are  often  thin- walled,  with  numerous 
pores;  i  to  2  mm.  in  length;  the  raw  fibres  generally  brown  and  rough. 

Coir. 

Stegmata  absent,  hence  the  fibres  are  not  accompanied  by  silicified 
elements (see  5). 

5.  Fibre-bundles  covered  externally  at  intervals  with  crystals  of  cal- 
cium oxalate,  at  times  up  to  0.5  mm.  in  length;  lustrous,  with  quadrangular 
sections,  chisel-shaped  at  the  ends,  hence  they  appear  as  thick,  needle- 
shaped  crystals;    when  present  in  large  numbers  these  crystals  occur  in 
long  rows  which  are  frequently  visible  to  the  naked  eye,  and  always  easily 
recognizable   under   the   microscope,   especially   in   the   ash.     The   fibre- 
bundles  are  mostly  thick,  and  their  outer  fibres  (as  a  result  of  their  prep- 
aration) frequently  contain  fissures  or  are  torn;    thickness  of  the  walls 
very  uneven ;  fibres  often  much  widened  at  the  middle Pita  hemp. 

Without  crystals,  generally  thin;  in  cross-section  usually  less  than 
100  fibres  to  a  bundle;  thickness  of  walls  and  lumen  very  uniform.  .  (see  6). 

6.  Sections  mostly  round,  not  very  compact;    lumen  usually  thinner 
than  the  wall,  but  never  a  single  line;   in  section  round  or  oval;  vascular 
tissue  in  but  small  amount New  Zealand  flax. 

Sections,  on  one  side  at  least,  polygonal;  section  of  lumen  polygonal, 
with  angles  more  or  less  sharp;  generally  as  wide  or  wider  than  the  wall; 
vascular  tissue  frequent .Aloe  hemp. 

7.  Fibres  mostly  rope-shaped,  twisted,  externally  streaked,  generally 
possessing  fine  granules  or  marked  with  little  lines,  therefore,  rough;   thin 
to  thick  walls;  cross-sections  squeezed  together,  or  round  to  kidney-shaped, 
hence  the  fibre  has  more  or  less  the  shape  of  a  flat  band;  section  of  lumen 
more  or  less  arched,  line-shaped,  frequently  containing  yellow  marrow; 
consists  of  pure  cellulose  with  the  exception  of  the  thin  cuticle Cotton. 

Fibres  not  twisted,  smooth  externally,  and  without  longitudinal  mark- 
ings; fibres  not  flat,  sections  round;  walls  generally  very  thin;  sometimes, 
however,  they  are  thick;  lignified,  scarcely  swelling  in  ammoniacal  copper 

oxide Vegetable  down  1     ,       ^ 

Vegetable  silks]    ' 

8.  Fibres  on  the  inside  possess  from  2  to  5  broad  ridges,  which  at  times 
are  very  noticeable,  at  others  scarcely  visible;   they  run  lengthwise  in  the 
fibre,  and  in  section  are  semicircular;    on  this  account  the  walls  appear 
unequal  in  thickness  when  viewed  longitudinally;   the  maximum  thickness 
is  about  35  [A Vegetable  silks  (see  9). 

Fibres  without  ridges;   maximum  thickness  mostly  30  to  35  (A 

Vegetable  down  (see  12). 

9.  Largest  diameters  50  to  60  u.;  length  3.5  to  4.5  cm (see  10). 

Largest  diameters  35  to  45  [A;  length  1.5  to  4  cm (see  n). 


510  THE  TEXTILE   FIBRES 

10.  Fibres  contracted  at  the  lower  end,  and  directly  above  abruptly 
swelling,  becoming  80  ;j.  thick;    the  under  portion  of  the  swollen  area 
contains  numerous  pore-canals;    fibres  feather-like  or  brush-like,  arising 
from  a  straight  shaft Vegetable  silk  from  Senegal. 

Contrary  to  the  above  the  fibres  originate  from  one  point,  like  a 
fan;  remarkably  strong,  curved  backward;  very  firm. 

Vegetable  silk  from  India. 

Like  the  foregoing,  but  the  fibre  is  stiff,  straight,  weak,  and  brittle. 

Cnlotropis  procera. 

11.  Thickened    ridges    very    noticeable;     in    the    cross-sections    often 
occurring  in  the  form  of  a  semicircle;   bound  together  in  a  strictly  reticu- 
lated manner Vegetable  silk  from  Asdcpias  cornuti. 

Thickened  ridges  indistinct,  projecting  but  slightly  in  the  cross-sec- 
tion  Vegetable  silk  from  Asdeplas  citrassamca. 

12.  Raw  fibre,  yellowish;    broadened  at  the  lower  end  (up  to  50  JJL); 
also  recticular  thickening  or  transverse  markings;  wall  i  to  2  ^  thick. 

Bombax  cotton. 

Raw  fibre,  brown;  the  lower  end  contracted  and  not  showing  reticu- 
lated thickenings;  fibre  almost  altogether  thin-walled,  though  just  at  the 
lower  end  very  thick- walled Cochlospennum  gossypium. 

13.  Thick-fibre-bundles,    whose    outer    surface    contains    at    intervals 
series  of  thick  silicious  plates,  having  sharp  idented  edges  and  a  round, 
hollow  space .  .  .- Manila  hemp  (see  under  4). 

Silicious  plates  absent;  lengthwise  the  lumen  often  exhibits  remarkable 
contractions,  while  the  wall  is  very  uneven  in  thickness;  at  intervals, 
indeed  the  lumen  is  almost  entirely  interrupted;  joints  and  transverse 
fissures  alpng  the  fibre;  transverse  markings  and  lines,  which  appear 
somewhat  like  zones  or  knots,  are  completely  lacking,  or  are  very  rare  and 
indistinct;  completely  lignified,  hence  colored  yellow  with  iodin  and  sul- 
phuric acid (see  14). 

Silicious  plates  absent,  also  remarkable  contractions  of  the  lumen; 
thickness  of  the  walls  very  uniform;  joints  and  fissures  along  the  fibre, 
transverse  lines  and  markings  frequent,  hence  the  fibre  often  appears 
as  if  it  contains  swollen  knots;  unlignified,  or  only  lignified  on  the  external 
layer  of  membrane,  hence  lengthwise  the  fibre  is  colored  blue  with  iodin 
and  sulphuric  acid  or  violet  or  green,  or  at  the  most  colored  yellow  in 
places (see  1 7). 

14.  Exterior  layers  of  membrane  narrow  and  showing  the  same  colora- 
tion with  iodin  and  sulphuric  acid  as  the  inner  layers,  hence  the  same 
as  the  entire  cross-section;   the  lumen  hardly  ever  completely  interrupted. 

(see  15). 

Median  layer  in  sections  wide;  colored  considerably  darker  with 
iodin  and  sulphuric  acid;  lumen  often  completely  interrupted  .  .  .  (see  16). 

15.  Lumen  in  general  large,  diameter  as  wide  or  only  a  little  narrower 


ANALYSIS   OF  THE  TEXTILE   FIBRES 


511 


than  the  wall;   in  section  round  or  oval,  seldom  as  a  point;   no  crystals  of 

calcium  oxalate True  jute. 

Lumen  usually  small,  diameter  much  narrower  than  the  thick  wall  in 
section  frequently  as  a  point;  crystals  of  calcium  oxalate  of  frequent 
occurrence  (detected  by  ignition)  Pseudo-jute  (Abelmoschus  (see  Fig.  139). 
1 6.  Lumen  almost  always  considerably  smaller  than  the  wall;  ends 
usually  very  thick-walled  and  narrow;  calcium  oxalate  crystals  of  fre- 
quent occurrence Pseudo-jute  (Urena  sinuata). 


FIG.  139. — Abelmoschus  Jute.     (X325.)     (Hohnel.)     /,  longitudinal  view;  q,  cross- 
section;  e,  ends;  L,  small  lumen;  v,  narrowing  of  lumen;  m,  median  layer. 


Lumen  frequently  as  wide  as  or  wider  than  the  wall,  mostly  narrower 
however;  ends  broad  and  blunt Gambo  hemp. 

17.  The  lumen  in  the  middle  portion  of  the  fibre  generally  line-shaped, 
much  narrower  than  the  wall;  ends  never  blunt,  always  sharply  pointed; 
sections  isolated  or  in  small  groups,  regular  in  diameter,  sharp-angled  and 
straight-sided  polygonals;  without  separate  median  layer;  iodin  and 
sulphuric  acid  colors  the  entire,  section  blue  or  violet;  the  lumen  in  the 
cross-section  is  very  small,  or  as  a  point,  containing  a  marrow  which 
is  colored  yellow  with  iodin  and  sulphuric  acid Linen  or  Flax. 


512  THE  TEXTILE  FIBRES 

Lumen,  at  least  in  the  central  portion  of  the  fibre,  always  much 
thicker  than  the  walls;  in  section  generally  more  or  less  flattened,  nar- 
row to  broad,  egg-shaped  or  oval.  Fibre  ends  blunt,  never  sharply  pointed; 
sections  almost  never  sharp-angled  polygonals,  but  more  or  less  oval  or 
elliptical,  and  with  a  rounded  boundary (see  18). 

18.  Breadth  of  fibre  up  to  80  ^;  maximum  length  15  to  60  mm.;  sec- 
tions always  in  compact  groups,  which  often  consist  of  many  fibres,  with 
thinner  or  thicker  layers  of  membrane,  which  are  colored  yellow  with  iodin 
and  sulphuric  acid,  hence  the  fibre  is  never  colored  a  pure  blue,  but  dirty 
blue  to  greenish,  and  in  places  yellow;  ends  often  have  side  branches  pro- 
jecting  ; (see  19). 

19.  Lignified  exterior  membranes  very  thin;   lumen  in  section  narrow, 
very  seldom  broad,  fissure-like  or  line-shaped,  often  branched,  without 
marrow Hemp. 

Lignified  exterior  layers  often  as  wide  as  the  interior  layers,  or  wider; 
the  interior  layers  are  often  loosened  in  places  from  the  exterior  ones 
where  they  are  thin;  lumen  in  section  scarcely  ever  narrow  or  fissure- 
shaped,  but  broad,  oval,  or  long;  often  containing  a  yellowish  marrow. 

Sunn  hemp. 

1 6.  Analysis  of  Bleached  Cotton. — In  the  bleaching  of 
cotton  the  main  object  is  to  remove  all  impurities  from  the  fibre 
leaving  only  the  pure  cellulose  as  the  resulting  product  without, 
however,  disintegrating  and  weakening  the  structure  of  the 
fibre  itself.  In  the  processes  of  bleaching,  alkalies,  acids  and 
strong  oxidizing  agents  are  employed;  hence  there  is  danger 
of  the  formation  of  oxycellulose,  a  condition  which  must  be 
avoided  if  good  bleaching  is  to  be  attained.  The  physical 
tests  which  should  be  applied  to  bleached  cotton  are:  (i) 
Color;  for  which  purpose  a  sample  should  be  examined  in  a  good 
north  light  and  compared  with  a  standard  sample.  There  is 
no  absolute  standard  of  white  ;  hence  such  a  color  test  must 
be  a  comparative  one.  (2)  Tensile  Strength;  this  should  be 
determined  with  reference  to  both  the  unbleached  and  bleached 
samples,  and  any  loss  due  to  the  process  of  bleaching  is  noted. 
This  loss  will  naturally  vary  with  the  nature  of  the  material 
being  bleached.  In  the  case  of  yarns,  the  tensile  strength  is 
generally  somewhat  less  on  bleaching,  but  the  loss  should  not 
be  over  5  per  cent  when  the  bleaching  is  properly  conducted. 
In  the  case  of  2 -ply  yarns  there  is  often  no  appreciable  loss 


ANALYSIS  OF  THE   TEXTILE  FIBRES 


513 


in  strength  due  to  bleaching.  In  bleached  cloth*  the  loss  in 
strength  due  to  bleaching,  if  any,  should  not  be  over  2  per 
cent.  In  many  cases  there  will  be  a  noticeable  increase  in  the 
strength  of  the  cloth,  due  no  doubt  to  a  shrinking  and  felting 
together  of  the  fibres.  (3)  Elasticity;  this  factor  is  usually 
reduced  to  some  extent  by  bleaching.  This  is  especially  the 
case  where  the  material  is  stretched  and  pulled  during  the 
processes  of  bleaching  and  washing. 

The  chemical  tests  to  be  applied  in  judging  the  quality  of 
bleached  cotton  are  as  follows:  (i)  Ash;  this  is  best  determined 
by  taking  10  gms.  of  the  sample  clipped  into  small  fragments 
and  burning  in  a  porcelain  crucible  until  a  complete  ash  is  left. 
The  weight  of  the  residual  ash  is  calculated  to  a  percentage  on 
the  weight  of  the  sample  taken.  The  ash  of  raw  cotton  will 
average  about  i  per  cent;  on  boiling  off,  this  amount  will  usually 
be  reduced  to  about  0.25  to  0.35  per  cent;  and  a  well-bleached 
cotton  should  not  give  more  than  o.io  per  cent  for  yarns  and 
light-weight  fabrics,  and  0.15  per  cent  for  heavy-weight  fabrics'. 
The  manner  and  degree  of  bleaching,  however,  will  have  much 
to  do  with  the  amount  of  ash.  Cotton  which  has  been  poorly 
boiled  out  and  only  partially  bleached  may  show  a  much  higher 

*  In  this  connection  O'Neill  gives  the  following  interesting  results,  made  to 
determine  the  tensile  strength  of  cotton -threads  before  and  after  bleaching: 


Average  Weight  Required  to  Break 
a  Single  Thread. 

Before  Bleaching. 

After  Bleaching. 

No. 
No. 
No. 
No. 

i  cloth,  weft-  threads  
i     '*   «  warp-threads.  .  .  . 

2      "                        ''          '      

3     " 

1714  grains 
3140      " 

3407      " 
3512      " 

2785  grains 
2020      " 
3708      " 
4025      " 

It  will  be  noticed  that  in  two  cases  out  of  three  the  warp-threads  are  stronger 
than  before,  and  it  may  be  safely  concluded  that  the  tensile  strength  of  cotton 
yarn  is  not  injured  by  careful  though  thorough  bleaching,  and  probably  it  may  be 
strengthened  by  the  wetting  and  pressure,  causing  a  more  complete  and  effective 
binding  of  the  separa.e  cotton  fibres,  the  twisting  together  of  which  makes  the 
yarn  stronger. 


514  THE  TEXTILE  FIBRES 

proportion  of  ash;  or  cotton  which  has  been  thoroughly  bleached 
but  not  well  washed,  or  which  has  been  washed  with  impure 
water,  may  also  show  in  ash  as  high  as  0.25  to  0.50  per  cent. 
Cotton  which  has  been  overbleached  by  the  use  of  too  strong 
a  solution  of  bleaching  powder  will  also  usually  show  a  propor- 
tion of  ash  greater  than  that  which  is  allowed.  The  determina- 
tion of  the  amount  of  ash  is  an  excellent  control-test  in  ascer- 
taining the  quality  of  the  bleaching.  A  frequent  defect  in  the 
bleaching  of  cloth  and  knit-fabrics  is  that  caused  by  portions 
of  the  fabric  coming  in  contact  with  strong  solutions  of  the 
chemic,  which  is  subsequently  only  incompletely  removed. 
This  results  in  a  discoloration  and  weakening  of  the  goods,  though 
the  defect  may  not  become  apparent  until  after  the  goods  have 
been  stored  for  some  months.  In  all  such  cases  the  amount 
of  ash  will  be  abnormally  high  (from  0.25  to  0.50  per  cent). 
(2)  Oxycellulose ;  when  cotton  is  bleached  with  solutions  of 
chloride  of  lime  there  is  nearly  always  more  or  less  oxycellulose 
formed.  This  is  also  true  when  the  cotton  has  been  improperly 
boiled  out  previous  to  bleaching.  The  presence  of  oxycellulose 
to  any  considerable  extent  in  bleached  cotton  fabrics  leads  to 
various  defects,  such  as  tendering  of  the  fibre,  discoloration 
and  improper  and  uneven  absorption  of  dyestuff  if  the  fabric 
is  subsequently  dyed.  There  are  a  number  of  tests  to  show  the 
presence  of  oxycellulose:  (a)  As  oxycellulose  has  a  greater 
attraction  for  certain  basic  dyestuffs  than  ordinary  cotton,  by 
staining  the  fabric  with  a  dilute  solution  of  methylene  blue  the 
presence  of  oxycellulose  may  be  detected.  In  applying  the  test 
the  sample  should  be  well  washed,  treated  for  thirty  minutes 
with  cold  dilute  nitric  acid  (2°  Be.),  again  washed,  treated 
with  boiling  sodium  bisulphite  solution  (i°  Be.)  for  fifteen 
minutes,  washed,  treated  with  dilute  hydrochloric  acid  (2° 
Be.)  for  thirty  minutes,  and  finally  washed  with  water.  The 
sample  so  prepared  is  then  steeped  for  twenty  minutes  in  a 
i10  per  cent  solution  of  methylene  blue,  rinsed  and  dried.  Por- 
tions of  the  fabric  which  may  contain  oxycellulose  will  appear 
considerably  darker  in  color,  (b)  Ordinary  cotton  when  treated 
with  an  iodin  solution  gives  a  yellow  coloration  changed  to 


ANALYSIS  OF  THE   TEXTILE  FIBRES  515 

blue  with  sulphuric  acid,  but  oxycellulose  gives  an  immediate 
blue  color  which  is  destroyed  by  sulphuric  acid.*  (c)  A  more 
satisfactory  test  for  oxycellulose  is  to  heat  the  fabric  for  fifteen 
minutes  with  10  per  cent  Fehling's  solution  on  the  hot  water- 
bath.  After  rinsing  with  water,  red  cuprous  oxide  will  be  found 
deposited  wherever  oxycellulose  is  present,  f  Before  carrying 
out  this  test  all  sizing  and  finishing  compounds  should  be 
removed  from  the  sample,  (d)  The  sample  is  treated  with  a 
dilute  solution  of  benzopurpurin,  then  rinsed  with  dilute  sul- 
phuric acid,  and  finally  washed  with  water  until  the  red  color 
of  ordinary  cotton  reappears.  Any  portions  containing  oxycel- 
lulose will  remain  as  bluish  black  stains,  (e)  Yieweg  makes  a 
determination  of  what  is  termed  the  acid  index,  as  follows: 
3.2  gms.  of  the  dried  bleached  cotton  are  boiled  for  fifteen  minutes 
with  50  c.c  of  a  semi-normal  solution  of  caustic  soda.  The 
excess  of  soda  is  then  titrated  with  a  semi-normal  solution  of 
sulphuric  acid  using  phenolphthalein  as  the  indicator.  The 
amount  of  caustic  soda  neutralized  by  the  cotton  calculated  to 
a  percentage  basis  gives  the  acid  index,  and  represents  the 
alkali  neutralized  in  decomposing  and  dissolving  the  hydro- 
cellulose  and  oxycellulose  present  in  the  bleached  fibre.  J  (/") 
Another  test  for  oxycellulose  which  is  said  to  be  very  reliable 

*  Vetillart,  Bull.  Soc.-Ind.  Rouen,  1883,  p.  233. 

f  This  test  may  be  carried  out  in  a  quantitative  manner,  giving  what  is  known 
as  the  "'copper  index."  Proceed  as  follows:  3  grams  of  bleached  cotton  are  placed 
in  a  \\  litre  flask,  and  300  c.c.  of  boiling  water  and  50  c.c.  of  Fehling's  solution 
added.  The  mixture  is  boiled  for  fifteen  minutes,  using  a  reflux  condenser  so  as 
to  avoid  loss  of  liquid.  Then  filter  and  wash  until  the  wash-water  is  free  from 
copper  salts.  The  cellulose  remains  on  the  filter  with  the  precipitate  of  cuprous 
oxide.  This  is  treated  in  a  porcelain  dish  with  15  c.c.  of  nitric  acid.  The  dis- 
solved copper  is  filtered  off,  and  its  amount  may  be  determined  by  electrolysis, 
or  quantitatively  by  the  usual  methods.  This  amount  of  copper  calculated 
to  percentage  on  the  amount  of  cotton  taken  for  analysis  gives  the  copper  index, 
and  measures  the  amount  of  oxycellulose  and  hydrocellulose  present.  (See 
Schwalbe,  Zeit.  angew.  Chem.,  1910,  p.  924.)  In  carrying  out  this  test  the  use 
of  cork  or  rubber  stoppers  should  be  avoided,  as  these  will  cause  the  precipitation 
of  red  cuprous  oxide.  The  apparatus  used  should  have  ground  glass  joints. 

t  Piest  (Zeit.  angew.  Chem.,  1910,  p.  1222)  has  compared  this  method  with  that 
of  the  copper-index  method  of  Schwalbe,  and  concludes  that  the  latter  factor 
is  preferable  as  an  accurate  indication  of  the  amount  of  oxidized  cellulose  present 
in  bleached  fabrics. 


516  THE  TEXTILE  FIBRES 

is  as  follows:  A  few  drops  of  a  suspension  of  indanthrene  yellow 
(prepared  by  dissolving  some  of  the  dried  paste  of  the  dyestuff  in 
strong  sulphuric  acid,  precipitating  by  pouring  in  to  cold  water,  and 
neutralizing)  are  added  to  a  10  per  cent  solution  of  caustic  soda, 
and  the  fabric  to  be  tested  is  passed  through  the  mixture  and 
slightly  squeezed.  The  material  is  then  held  over  a  beaker 
in  which  water  is  vigorously  boiling.  Within  a  minute  a  deep  blue 
stain  appears  wherever  oxycellulose  or  hydrocellulose  is  present, 
while  the  rest  of  the  fabric,  if  it  has  been  carefully  bleached, 
shows  no  trace  of  blue  for  at  least  five  minutes.  If  the  cotton 
is  next  washed,  soured,  and  scoured  with  soap,  the  unaffected 
dye  is  readily  removed,  but  wherever  oxycellulose  has  formed 
the  color  is  firmly  fixed.* 

*See  Scholl,  Berichte,  1911,  p.  1312;  and  Ermen. 


CHAPTER  XIX 
ANALYSTS  OF  TEXTILE  FABRICS  AND  YARNS 

i.  Wool  and  Cotton  Fabrics. — The  finishing  materials  and 
coloring  matter  should  be  removed  as  far  as  possible  by  boiling 
a  weighed  sample  of  the  fabric,  first  in  a  i  per  cent  solution  of 
hydrochloric  acid,  then  in  a  dilute  solution  of  sodium  car- 
bonate (about  a  -0V  per  cent  solution),  'and  finally  in  water. 
It  is  then  air-dried  and  reweighed;  the  loss  will  represent 
finishing  materials.  A  portion  of  the  material  is  then  dried  at 
100°  C.,  for  an  hour  (or  until  constant  weight  is  obtained)  and 
weighed;  this  weight  will  represent  the  actual  amount  of 
true  fibre  present  in  the  sample,  and  the  loss  will  correspond 
to  moisture.  Then  steep  for  twelve  hours  in  a  mixture  of 
equal  parts  of  sulphuric  acid  and  water,  and  mix  with  three 
volumes  of  alcohol  and  water  ;  filter  off  the  dissolved  cotton 
and  wash  the  residue  of  wool  well  with  alcohol.  Dry  at  100° 
C.,  and  weigh;  this  will  give  the  amount  of  wool  present.* 
The  following  example  will  illustrate  this  method : 

Grams. 

Sample  weighed 3.62 

After  treatment  with  acid  and  alkali 3.17 

Finishing  materials,  etc o .  45 

After  drying  at  100°  C 2.77 

Loss  as  water o .  40 

Wool  left  after  treating  with  acid i  .96 

Cotton,  by  difference ! o .  81 

*  By  this  treatment  the  wool  suffers  a  loss  of  about  2\  per  cent. 

517 


518  THE  TEXTILE  FIBRES 

Hence  the  composition  of  this  sample  would  be  as  follows: 

Per  Cent. 

Finishing  materials 1 2 . 43 

Moisture 1 1 . 05 

Wool 54.14 

Cotton 22 . 38 


100.00 


Another,  and  perhaps  a  better,  method  for  determining  the 
relative  amounts  of  wool  and  cotton  in  a  mixed  fabric  or  yarn, 
especially  when  the  cotton  is  present  in  rather  large  proportion, 
is  to  remove  the  wool  by  treatment  with  a  dilute  boiling  solu- 
tion of  caustic  potash.  The  estimation  is  carried  out  in  the 
following  manner: 

The  sample  to  be  tested  is  treated  with  hydrochloric  acid  and 
sodium  carbonate  solutions  as  before,  in  order  to  remove  finish- 
ing materials,  and  after  thorough  washing  is  dried  at  100°  C. 
and  weighed.  This  gives  the  weight  of  the  dry  fibres.  The 
weighed  sample  is  then  boiled  for  twenty  minutes  in  a  5  per  cent 
solution  of  caustic  potash.*  The  residue  is  well  washed  in 
fresh  water,  and  redried  at  100°  C.  and  weighed.  The  residue 
consists  of  cotton,  the  wool  having  been  dissolved  by  the  caustic 
potash.  If  the  residue  becomes  disintegrated  and  cannot  be 
washed  and  dried  as  one  piece,  it  should  be  collected  on  a 
tared  filter  (one  which  has  been  dried  at  100°  C.  and  weighed) 
and  well  washed  with  water,  then  dried  at  100°  C.,  and  weighed. 
The  tared  weight  of  the  filter  subtracted  from  the  latter  will 
give  the  weight  of  the  cotton  particles. 

In  case  yarns  are  to  be  analyzed,  the  preliminary  treatment 
should  consist  of  a  thorough  scouring  with  soap.  After  drying 
in  the  air,  the  loss  in  weight  should  be  recorded  as  grease  and 
miscellaneous  dirt.  On  then  drying  at  100°  C.  to  constant 
weight,  the  loss  will  represent  moisture,  and  the  residue  dry 
fibre.  This  is  then  analyzed  as  in  the  manner  above  described. 


*  It  is  not  advisable  to  use  caustic  soda  instead  of  caustic  potash,  as  the  results 
obtained  are  not  as  satisfactory. 


ANALYSIS  OF  TEXTILE   FABRICS  AND   YARNS        519 

Examples: 

(a)  Analysis  of  a  cloth  sample: 

Grams. 

Weight  of  sample 5-42 

After  treatment  with  acid  and  alkali .  .  ^ .  10 


Finishing  materials,  etc 0.32 

After  drying  at  100°  C 4 . 26 

Loss  as  water o .  84 

Cotton  left  after  boiling  with  caustic  alkali .  .  . 2 .82 

Wool,  by  difference i . 44 

Hence  the  composition  of  this  sample  would  be: 

Per  Cent. 

Finishing  materials 5-98 

Moisture v 15 . 50 

Cotton 52 . 03 

Wool 26 . 49 


Since  the  cotton  itself  suffers  a  slight  loss  on  boiling  with 
caustic  potash,  it  is  customary,  as  a  correction,  to  add  to  the 
cotton  found  5  per  cent  of  its  weight,*  and  to  subtract  a  cor- 
responding amount  from  that  of  the  wool.  On  applying  this 
correction  the  result  of  the  above  analysis  would  become: 

Per  Cent. 

Finishing  materials 5 . 98 

Moisture J5-5O 

Cotton 54-63 

Wool 23 . 89 


Figured  on  the  weight  of  the  dry  fibre,  the  relative  amounts 
of  the  two  fibres  in  the  above  samples  would  be : 

Per  Cent. 

Cotton 69 . 5 

Wool 30.5 


100. o 


*  The  author  has  found  that  the  cotton  will  not  lose,  as  a  rule,  more  than  3 
per  cent. 


520  THE  TEXTILE   FIBRES 

Since,  however,  in  making  mixes,  the  dry  weights  of  the 
fibres  are  not  taken,  we  may  assume  the  weight  to  include  the 
normal  amount  of  moisture  held  by  each  fibre.  As  the  normal 
amount  of  moisture  for  cotton  is  about  8  per  cent,  and  for  wool 
about  1 6  per  cent,  we  may  approximate  very  closely  to  the  true 
composition  of  this  sample  by  adding  to  the  dry  weights  of  the 
fibres  their  respective  amounts  of  moisture;  the  relative  amounts 
of  cotton  and  wool  then  become: 

Grams. 

Weight  of  cotton  found 2.82 

Add  5  per  cent  correction 0.14 

2.96 

This  represents  92  per  cent  of  air-dry  cotton. 

Grams. 
Hence  air-dry  cotton  would  be 3.22 

Weight  of  wool   found i .  44 

Subtract  correction  for  cotton.  .  . o.  14 

1.30 

This  represents  84  per  cent  of  air-dry  wool. 

Hence  air-dry  wool  would  be i .  54 

Therefore  the  relative  amounts  of  cotton  and  wool  on  this 
basis  would  be: 

Per  Cent. 

Cotton x. 67.6 

Wool 32.4 

(b)  Analysis  of  a  yarn: 

Grams. 

Weight  of  sample 5-65 

Scoured  in  soap,  washed  and  air-dried 4-97 

Grease,  etc o .  68 

Dried  at  100°  C 4.32 

Loss  as  moisture 0.65 

Weight  of  filter-paper  dried  at  100°  C i .  16 

Weight  of  filter  and  residue  of  cotton  dried  at  100°  C .     3 . 66 

Weight  of  dry  cotton 2 . 50 

Add  5  per  cent  correction 2.62 

Correct  for  moisture  at  8  per  cent 2 . 85 

Weight  of  dry  wool  by  difference  (with  correction) ....      i .  70 
Correct  for  moisture  at  16  per  cent 2 . 02 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS        521 
Hence  the  composition  of  this  yarn  may  be  expressed  as: 

Per  Cent. 

Grease,  etc 12.00 

Moisture 1 1 . 50 

Cotton    44 .25 

Wool * 32 . 25 


100.00 

And  the  relative  proportion  of  the  two  fibres  would 'be  as 
follows: 

Dry  at  100°  C.      Air-dry. 

Cotton 60.7  58.5- 

Wool 39.3  41.5 


The  following  scheme  for  the  analysis  of  a  fabric  containing 
wool  and  cotton  is  given  by  Herzfeld:* 

(a)  Estimation  of  moisture. — Five  grams  of  the  fabric  are 
dried  at  100°  C.  until  the  weight  is  constant.     The  loss  indicates 
the  amount  of  moisture  present. 

(b)  Estimation  of  cotton. — Five  grams  of  the  fabric  are  boiled 
for  one-quarter  hour  with  100  cc.  of  a  o.i  per  cent  solution  of 
caustic  soda,  then  washed  with  water  and  treated  with  luke- 
warm 10  per  cent  caustic  potash  solution,  until  the  wool  fibres 
are  completely  dissolved,  if  necessary  the  liquid  being  raised 
to  the  boiling-point.     The  residue  is  washed  with  water,  then 
treated  for  one-quarter  hour  with  dilute  hydrochloric  acid,f  then 
washed  again  with  water,  boiled  for  one-quarter  hour  with  dis- 
tilled water,  washed  with  alcohol  and  ether,  and  finally  dried  at 
100°  C.  until  constant  weight  is  obtained.     The  residue  is  cotton. 

(c)  Estimation  of  wool. — Five  grams  of  the  cloth  are  boiled 
with  100  cc.  of  a  dilute  solution  of  soda-ash  for  one-quarter  hour, 
washed  with  water,  and  steeped  for  two  hours  in  sulphuric  acid 
of  58°  Be.J  then  washed  with  water,  and  boiled  for  one-quarter 

*  Yarns  and  Textile  Fabrics,  p.  145. 

t  The  object  of  washing  with  dilute  hydrochloric  acid  is  to  neutralize  the 
excess  of  caustic  alkali  in  the  fibre,  so  that  it  may  be  more  readily  removed,  as 
caustic  alkali  remains  in  the  fibre  very  pertinaciously. 

t  Acid  of  this  strength  is  somewhat  too  strong,  as  it  will  decompose  the  wool 
to  a  considerable  extent.  It  is  not  safe  to  employ  sulphuric  acid  of  greater 
strength  than  one  part  of  acid  to  one  part  of  water  by  volume. 


522  THE  TEXTILE  FIBRES 

hour  with  water,  and  finally  washed  with  alcohol  and  ether, 
and  dried  at  100°  C.,  until  constant  weight  is  obtained.  The 
residue  is  wool. 

(d)  Dressing  and  dye  are  found  by  difference. 

When  a  rough,  approximate  analysis  of  a  wool-cotton  fabric  is 
desired,  it  will  be  sufficient  only  to  weigh  the  sample,  boil  for 
fifteen  minutes  in  a  5  per  cent  solution  of  caustic  potash,  wash 
well  in  acidulated  water,  then  in  fresh  water,  and  dry  in  the  air. 
On  reweighing,  the  amount  of  cotton  will  be  ascertained,  while 
the  loss  in  weight  will  represent  the  amount  of  wool.  Results 
attained  by  this  process  are  usually  sufficiently  accurate  to 
give  one  a  practical  idea  of  the  approximate  relative  amounts 
of  wool  and  cotton  present  in  a  sample  of  mixed  goods. 

Another  method  for  the  separation  of  wool  from  cotton  in 
their  quantitative  estimation  is  treatment  of  the  mixed  fibres 
with  an  ammoniacal  solution  of  copper  oxide,  whereby  the  cot- 
ton is  dissolved;  and  after  washing  and  drying,  the  residue  of 
wool  is  weighed.  This  method,  however,  is  not  very  satisfactory, 
as  it  is  difficult,  in  the  first  place,  to  obtain  a  complete  and 
thorough  solution  of  the  cotton;  and  in  the  second  place,  the 
wool  will  be  considerably  affected  by  this  treatment  and  more 
or  less  decomposed.  Consequently  the  results  obtained  by 
this  method  are  not  very  accurate,  and  it  cannot  be  recommended. 

2.  Wool  and  Silk.— Silk  is  soluble  in  strong  hydrochloric 
acid,  whereas  wool  is  not  soluble  in  this  reagent  to  any  extent. 
Hence  this  method  may  be  utilized  for  the  quantitative  estimation 
of  the  two  fibres  when  occurring  together.  The  sample  is 
first  treated  with  acid  and  alkali  in  the  manner  already  described 
in  order  to  remove  foreign  material  other  than  actual  fibre. 
It  is  then  dried  and  weighed;  then  immersed  in  cold  concen- 
trated hydrochloric  acid  (about  40  per  cent  strength).  The 
silk  dissolves  almost  immediately.  The  residue  is  collected, 
washed  thoroughly,  dried  again,  and  weighed.  The  loss  in 
weight  represents  silk,  while  the  weight  of  the  residue  repre- 
sents wool.  Another  method,  and  one  which  is  very  satis- 
factory, is  to  dissolve  the  silk  by  treatment  with  an  ammoniacal 
solution  of  nickel  oxide,  in  which  reagent  the  silk  is  very  readily 


ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS         523 

soluble  even  in  the  cold.  It  only  requires  a  treatment  of  about 
two  minutes  to  completely  dissolve  the  silk  in  most  silk  fabrics 
other  than  plush.  Richardson  *  found  that  by  this  treatment 
cotton  lost  only  0.45  per  cent  in  weight  and  wool  only  0.33  per 
cent.  As  silk  in  plush  goods  and  similar  fabrics  is  much  more 
difficult  to  dissolve,  it  is  recommended  to  boil  such  material 
with  the  nickel  solution  for  ten  minutes  under  a  reflux  con- 
denser. By  this  treatment  cotton  will  lose  only  0.8  per  cent 
in  weight.  The  nickel  solution  is  best  prepared  by  dissolving 
25  gms.  of  crystallized  nickel  sulphate  in  80  cc.  of  water;  add 
36  cc.  of  a  20  per  cent  solution  of  caustic  soda,  carefully  neutraliz- 
ing any  excess  of  alkali  with  dilute  sulphuric  acid.  The  pre- 
cipitate of  nickel  hydroxide  is  then  dissolved  in  125  cc.  of  strong 
ammonia,  and  the  solution  diluted  to  250  cc.  with  water.  Instead 
of  the  above  reagent,  a  boiling  solution  of  basic  zinc  chloride 
may  be  employed  for  the  purpose  of  dissolving  the  silk.  This 
latter  solution  is  obtained  by  heating  together  1000  parts  of 
zinc  chloride,  850  parts  of  water,  and  40  parts  of  zinc  oxide  until 
complete  solution  is  effected.  Richardson  recommends  that 
the  sample  to  be  examined  should  be  plunged  two  or  three  times 
into  the  boiling  solution  of  zinc  chloride,  care  being  taken  that 
the  total  time  of  immersion  does  not  exceed  one  minute.  The 
zinc  chloride  solution  should  be  sufficiently  basic  and  concen- 
trated in  order  to  obtain  good  results.  Under  the  best  condi- 
tions, cotton  loses  about  0.5  per  cent  in  weight,  and  wool  from 
1.5  to  2.0  per  cent. 

The  chief  difficulty  attached  to  the  use  of  the  zinc  chloride 
solution  is  that  it  requires  a  long  and  tedious  washing  to  remove 
all  of  the  zinc  salt  from  the  residual  fibres.  It  is  best  to  wash 
with  water  acidulated  with  hydrochloric  or  acetic  acid. 

3.  Silk  and  Cotton. — The  methods  given  above  for  separat- 
ing silk  from  wool  may  also  be  used  for  the  separation  and 
quantitative  determination  of  silk  in  fabrics  containing  this 
fibre  in  conjunction  with  cotton. 

Another  method  for  separating  silk  from  cotton  is  by  the 
use  of  an  alkaline  solution  of  copper  and  glycerol,  which  serves 

*  Jour,  Soc,  Chem.  Ind.,  1893,  p.  430. 


524  THE  TEXTILE  FIBRES 

as  an  excellent  solvent  for  the  silk.  The  reagent  is  prepared 
as  follows:  Dissolve  16  gms.  of  copper  sulphate  in  150  cc. 
of  water,  with  the  addition  of  10  gms.  of  glycerol;  then  gradually 
add  a  solution  of  caustic  soda  until  the  precipitate  of  copper 
hydrate  which  is  at  first  formed  just  redissolves.  This  solution 
readily  dissolves  silk,  but  is  said  not  to  affect  either  wool  or  the 
vegetable  fibres.  Richardson,  however,  has  found  that  cotton 
heated  with  this  solution  for  twenty  minutes  (the  time  neces- 
sary to  dissolve  silk  in  plush)  lost  from  i  to  1.5  per  cent  in  weight 
and  became  friable  and  dusty  on  drying;  while  woolen  fabrics 
lost  from  9  to  1 6  per  cent  in  weight.  Hence  the  reagent  would 
be  useless  in  the  analysis  of  fabrics  containing  wool. 

4.  Wool,  Cotton,  and  Silk. — Samples  of  shoddy  frequently 
contain  all  three  of  these  fibres  present  in  greater  or  lesser 
amount,  and  often  it  is  desirable  to  know  at  least  the  approx- 
imate amounts  of  each  fibre  in  the  mixture.  A  method  of  pro- 
cedure recommended  is  the  following:  A  weighed  sample  of  the 
material  is  boiled  for  thirty  minutes  in  a  i  per  cent  solution  of 
hydrochloric  acid,  washed,  and  then  boiled  for  thirty  minutes 
in  a  0.05  per  cent  solution  of  soda-ash.  This  preliminary  opera- 
tion is  similar  to  that  above  described  in  the  preceding  analyses, 
and  is  for  the  purpose  of  freeing  the  fibres  as  far  as  possible 
from  extraneous  foreign  matter.  After  thorough  washing 
and  air-drying,  the  weight  of  the  sample  is  again  taken,  and 
the  loss  will  represent  miscellaneous  foreign  matter.  The  sample 
is  then  dried  at  105°  C.  to  constant  weight;  the  loss  in  weight 
will  represent  moisture.  The  sample  is  then  divided  into  two 
weighed  portions;  the  first  is  treated  for  five  minutes  with  a 
boiling  solution  of  basic  zinc  chloride  prepared  as  above  described, 
washed  thoroughly  with  acidulated  water,  then  with  fresh 
water,  and  dried  at  100°  C.  again.  The  loss  in  weight  will 
represent  the  amount  of  silk  present.  The  second  portion 
of  the  sample  is  boiled  for  ten  minutes  in  a  5  per  cent  solution 
of  caustic  potash;  washed  thoroughly,  dried  at  100°  C.  and 
weighed.  This  weight,  with  a  correction  of  5  per  cent  added  to 
it,  will  represent  the  amount  of  cotton  present.  The  amount 
of  wool  is  obtained  by  taking  the  difference  between  the  total 


ANALYSIS   OF  TEXTILE   FABRICS  AND   YARNS        525 

weight  of  the  combined  fibres  and  the  sum  of  the  weights  of 
the  silk  and  cotton. 

Example: 

Grams, 

Sample  of  loose  shoddy  weighed 5 . 06 

Treated  with  acid  and  alkali,  and  air  dried 4-23 


Loss  as  foreign  matter o .  83 

Dried  at  100°  C 3.62 

Loss  as  moisture .  .  o .  61 


Divided  into  two  portions: 

Grams. 

(0)  weighed * 1.95 

(b)  weighed 1.67 

(a)  treated  with  zinc  chloride i .  73 

Loss  as  silk.  .  0.22 


(&)  treated  with  caustic  potash,  residue  as  cotton 0.34 

Loss  as  wool i .  33 


Hence  the  composition  of  this  sample  on  the  basis  of  dry 
fibre  would  be: 

Per  Cent. 

Silk 11.3 

Cotton 21.5 

Wool 67.2 


100.  o 


Von  Remont  gives  the  following  method  for  analyzing  fabrics 
containing  a  mixture  of  silk,  wool,  and  cotton.  Four  quantities 
(^4,  B,  C,  D)  of  2  gms.  each  of  the  air-dried  material  are  weighed 
out.  Portion  A  is  kept  aside,  and  each  of  the  other  three  is 
boiled  for  fifteen  minutes  in  200  cc.  of  water  containing  3  per 
cent  of  hydrochloric  acid.  The  liquid  is  decanted,  and  the 
boiling  repeated  with  more  dilute  acid.  This  treatment  removes 
the  size  and  the  major  portion  of  the  coloring  matter.  Cotton 
is  nearly  always  decolorized  quite  rapidly,  wool  not  so  readily, 
and  silk  but  imperfectly,  especially  with  black-dyed  fabrics. 


526  THE  TEXTILE  FIBRES 

The  samples  should  be  well  washed  and  squeezed  in  order  to 
remove  the  acid  liquor.  Portion  B  is  set  aside.  Portions  C 
and  D  are  then  placed  for  two  minutes  in  a  boiling  solution  of 
basic  zinc  chloride  (of  1.72  sp.gr.,  and  prepared  as  above 
described),  which  dissolves  any  silk  present.  They  are  then 
washed  with  water  containing  T  per  cent  of  hydrochloric  acid, 
and  again  with  pure  water,  until  the  washings  no  longer  show 
the  presence  of  zinc.  Portion  C  is  squeezed  and  set  aside. 
Portion  D  is  boiled  gently  for  fifteen  minutes  with  60  to  80 
cc.  of  caustic  soda  solution  (1.02  sp.gr.)  in  order  to  remove  any 
wool.  The  sample  is  then  carefully  washed  with  water.  The 
four  portions  are  next  dried  for  an  hour  at  100°  C.,  and  then 
left  exposed  to  the  air  for  ten  hours  in  order  to  allow  them  to 
absorb  the  normal  amount  of  hygroscopic  moisture.  The 
four  samples  are  "then  weighed,  and  calling  a,  b,  c,  and  d  their 
respective  weights,  we  shall  have 

a  —  b  =  dye  and  finishing  material ; 
b  —  c  =  silk ; 
c  —  d  =  wool ; 

d  =  cotton  (or  vegetable  fibre) . 

This  method  is  open  to  objections,  as  the  plan  of  using  air- 
dried  material,  then  drying  at  100°  C.,  and  subsequently 
exposing  to  the  air  again  before  reweighing,  is  liable  to  give  very 
erroneous  results.  Richardson  recommends  that  the  samples 
should  be  thoroughly  dried  at  100°  C.  before  being  weighed 
out,  and  the  treated  portions  should  subsequently  be  dried  at 
the  same  temperature  before  weighing.  In  order  to  prevent 
the  sample  from  absorbing  moisture  during  weighing,  it  is  best 
to  use  a  weighing-bottle  for  holding  the  dried  fibre.  The  sample 
before  drying  is  placed  in  a  weighing-bottle  (the  weight  of  which 
has  been  ascertained  previously)  and  heated  in  an  air-oven  at 
100°  C.  for  the  time  specified,  during  which  the  cover  of  the 
weighing-bottle  is  removed.  After  the  drying  process  is  com- 
pleted the  stopper  is  replaced  in  the  weighing-bottle;  the  latter 
is  taken  from  the  oven,  allowed  to  cool,  and  is  then  weighed. 


ANALYSIS  OF  TEXTILE   FABRICS  AND   YARNS        527 


The  difference  between  this  weight  and  the  weight  of  the  empty 
bottle  will  give  the  amount  of  dry  fibre. 

Treatment  with  a  boiling  solution  of  3  per  cent  hydro- 
chloric acid  for  the  purpose  of  removing  finishing  materials  is 
rather  too  severe,  as  the  acid  will  act  on  the  wool  and  the  cot- 
ton, sometimes  causing  considerable  error.  Boiling  with  a 
i  per  cent  solution  of  acid  for  ten  minutes  is  to  be  preferred. 

The  following  is  given  as  a  practical  method  to  determine  if 
shoddy  contains  cotton  and  silk  fibres:  Boil  10  gms.  of  the  shoddy 
to  be  tested  for  one  hour  in  400  cc.  of  water  containing  0.8  gm. 
of  alum,  0.3  gm.  of  tartar,  i  cc.  of  hydrochloric  acid,  o.i  gm.  of 
chrome,  and  0.05  gm.  of  bluestone.  Rinse  and  dye  with  0.3 
gm.  of  logwood  extract.  Rinse  and  dry.  The  undyed  fibres 
are  then  picked  out  and  examined;  cotton  will  remain  white, 
while  silk  will  be  colored  a  dingy  red. 

The  analysis  of  heavy  pile  fabrics  containing  a  mixture  of 
fibres  is  especially  difficult  unless  the  fabric  is  disintegrated. 
In  the  analysis  of  plush  for  the  amount  of  silk  present,  Richard- 
son suggests  treating  the  sample  with  a  boiling  solution  of  basic 
zinc  chloride  in  the  manner  previously  described;  but  when 
silk  is  to  be  determined  in  light  fabrics  (especially  in  the  presence 
of  wool),  it  is  best  to  treat  the  sample  for  one  to  three  minutes 
with  a  cold  solution  of  ammoniacal  nickel  oxide.  He  gives  the 
following  comparison  of  results  in  the  analysis  of  a  sample  of 
plush,  using  the  three  different  methods  for  dissolving  the  silk: 


By  Solution 
of  Ammoniacal 
Nickel  Oxide. 

By  Solution 
of  Basic 
Zinc  Chloride. 

By  Copper- 
glycerol 
Reagent. 

Moisture  and  finish 

II    34 

II    OO 

10  04 

Silk  

4^-60 

45  -00 

47  -°6 

Cotton  

43  .60 

44  oo 

42  .90 

Samples  of  plush  with  hard  cotton  backs  may  best  be  analyzed 
by  successive  treatment  with  acid  and  copper-glycerol  reagent. 
On  other  cotton  material,  however,  this  method  is  not  suitable; 
nor.  is  it  to  be  used  in  the  presence  of  wool,  as  this  fibre  is  con- 
siderably dissolved  by  the  copper-glycerol  reagent. 


528 


THE  TEXTILE  FIBRES 


The  following  table  by  Richardson  shows  a  comparison  of 
the  three  methods  employed  for  dissolving  silk : 


Fibre. 

Actually 
Present. 

Percentage  Obtained  by 

Ammoniacal 
Nickel  Oxide. 

Basic  Zinc 
Chloride. 

Copper-glycerol 
Reagent. 

Silk 

5.84 
76.31 
17.85 

5-92 
76.58 
17.50 

5-52 
80.08 
14.40 

18.80 
64.05 
17-15 

Wool 

Cotton      

The  ammoniacal  nickel  oxide  solution  appears  to  give  the 
best  results;  hence,  in  analyzing  a  sample  containing  silk, 
wool,  and  cotton,  it  is  best  first  to  remove  the  silk  by  means  of 
this  reagent.  The  insoluble  residue  left  after  this  treatment 
is  boiled  with  a  i  per  cent  solution  of  hydrochloric  acid,  washed 
well  in  fresh  water,  and  then  boiled  for  five  to  ten  minutes  in  a  2 
per  cent  solution  of  caustic  potash,  which  is  sufficient  to  remove 
completely  the  wool  without  materially  affecting  the  cotton. 

From  experiments  conducted  by  the  author's  students  * 
the  following  comparative  results  have  been  obtained  in  the 
analysis  of  textile  materials  by  the  different  methods  suggested. 

(a)  Analysis  of  wool-cotton  mixture : 


Fibre. 

Dissolving  Wool  by 
Caustic  Potash. 

Dissolving  Cotton 
by  Sulphuric  Acid. 

Theoret. 

Found. 

Theoret. 

Found. 

Cotton        

56.7 
43-3 

55-2 

44.8 

63.7 
36.3 

64.2 
35-8 

Wool                   

(b)  Analysis  of  wool-silk  mixture: 


Fibre. 

With  Hydrochloric 
Acid. 

With  Ammoniacal 
Nickel  Oxide. 

With  Basic  Zinc 
Chloride. 

Theoret. 

Found. 

Theoret. 

Found. 

Theoret. 

Found. 

Wool  

76.6 
23-4 

76.24 
23.76 

78.5 

21.5 

77-3 
22.7 

8i-7 
l8.3 

71-5 
28.5 

Silk  

*  See  Collingwood,  Textile  World  Record,  vo)   2Q,  pp.  874,  1193. 


ANALYSIS  OF  TEXTILE  FABRICS   AND  YARNS         529 

(c)  Analysis  of  cotton-silk  mixture: 


Fibre. 

With  Hydrochloric 
Acid. 

With  Ammoniacal 
Nickel  Oxide. 

With  Basic  Zinc 
Chloride. 

Theoret. 

Found. 

Theoret. 

Found. 

Theoret. 

Found. 

Cotton  
Silk        ,'.  .  . 

70 
30 

67-5 
32.5 

65.  12 

34-88 

64.42 
35-52 

71.11 
28.89 

70.13 
29.87 

(d)  Analysis  of  wool-cotton-silk  mixture: 


Fibre. 

Silk  by  Ammoniacal 
Nickel  Oxide;  Wool 
by  Caustic  Potash. 

Silk  by  Ammoniacal 
Nickel  Oxide;  Cotton 
by  Sulphuric  Acid. 

Theoret. 

Found. 

Theoret. 

Found. 

Wool  

41.2 
42.7 
16.1 

42.1 
41  .6 
17-3 

41.0 
48.1 
10.9 

39-0 
49.2 
n.  8 

Cotton 

Silk  

Fibre. 

Silk  by  Hydrochloric 
Acid;  Wool  by 
Caustic  Potash. 

Silk  by  Hydrochloric 
Acid;   Cotton  by 
Sulphuric  Acid. 

Theoret. 

Found. 

Theoret. 

Found. 

Wool      .    '..;•. 

38.9 
42.2 
18.9 

39-4 
38.0 

22.6 

28.6 
47-7 
23-7 

24.0 
48.8 
27.2 

Cotton  

Silk  

Fibre. 

Silk  by  Basic  Zinc 
Chloride;  Wool  by 
Caustic  Potash. 

Silk  by  Basic  Zinc 
Chloride;  Cotton 
by  Sulphuric  Acid. 

Theoret. 

Found. 

Theoret. 

Found. 

Wool  

59-o 

26.3 

14.7 

57-5 
24-4 
18.1 

63-5 
19.7 
16.8 

61.6 
2O.  O 

!8.4 

Cotton  . 

Silk 

From  a  consideration  of  these  results  it  would  appear  that 
in  the  analysis  of  wool-cotton  mixtures  the  rapidity  with  which 
the  caustic  potash  dissolves  the  wool  gives  this  method  a  slight 
preference  over  the  somewhat  slower  one  of  destroying  the 


530  THE  TEXTILE   FIBRES 

cotton  by  treatment  with  sulphuric  acid.  In  the  analysis  of 
wool-silk  materials  the  treatment  with  hydrochloric  acid  is 
slightly  better  than  by  the  use  of  ammoniacal  nickel  oxide. 
The  latter  reagent,  however,  is  the  better  to  use  for  dissolving 
the  silk  from  cotton-silk  mixtures,  as  the  cotton  is  too  readily 
attacked  by  the  concentrated  hydrochloric  acid.  In  the  analysis 
of  wool-cotton-silk  mixtures  the  only  proper  reagent  to  employ 
for  dissolving  the  silk  is  the  solution  of  ammoniacal  nickel 
oxide.  Though  the  use  of  this  reagent  is  rather  slow  compared 
with  the  acid,  it  is  thorough,  and  its  action  on  the  other  two 
fibres  is  but  slight. 

The  following  table  shows  the  corrections  to  be  applied  in  the 
calculations  of  results,  by  reason  of  the  action  of  the  different 
reagents  on  the  fibre  which  is  not  to  be  dissolved: 

(1)  Woof -cotton  mixtures: 

(a)  Wool  dissolved  by  caustic  potash;  correction  for 

loss  of  cotton 3.0  per  cent 

(b)  Cotton  dissolved   by  sulphuric  acid;   correction 

for  loss  of  wool 2.5 

(2)  Wool-silk  mixtures: 

(a)  Silk  dissolved  by  hydrochloric  acid;   correction 

for  loss  of  wool 0.5 

(b)  Silk    dissolved    by   ammoniacal    nickel    oxide; 

correction  for  loss  of  wool 1.5 

(c)  Silk  dissolved  by  basic  zinc  chloride;   correc- 

tion for  loss  of  wool 2.0 

(3)  Cotton-Silk  mixtures: 

(a)  Silk  dissolved  by  hydrochloric  acid;   correction 

for  loss  of  cotton 4.0 

(b)  Silk    dissolved    by    ammoniacal    nickel   oxide; 

correction  for  loss  of  cotton .  . i  .o 

(c)  Silk  dissolved   by   basic   zinc   chloride;   correc- 

tion for  loss  of  cotton 1.5 

Allen  *  also  recommends  the  ammoniacal  nickel  solution 
for  use  in  dissolving  silk  from  a  mixture  of  fibres.  His  method 
of  analyzing  a  textile  sample  is  as  follows:  The  yarn  or  fabric 
is  cut  up  very  fine  with  a  pair  of  scissors,  and  thoroughly  dried 

*  Commer.  Org.  Anal.,  vol.  4,  p.  523. 


ANALYSIS   OF  TEXTILE   FABRICS  AND   YARNS         531 

at  100°  C.  One  gram  of  the  material  thus  prepared  is  treated 
with  40  cc.  of  the  cold  ammoniacal  nickel  oxide  solution  for  two 
minutes.  The  liquid  is  then  filtered,  and  the  residue,  consist- 
ing of  wool  and  cotton,  is  digested  for  two  or  three  minutes 
in  a  boiling  solution  of  i  per  cent  hydrochloric  acid.  It  is 
then  washed  free  from  acid,  dried  at  100°  C.,  and  weighed. 
To  separate  the  wool  from  the  cotton  the  residue  is  boiled  with 
about  50  cc.  of  a  i  per  cent  solution  of  caustic  potash  for  ten 
minutes,  and  the  solution  filtered.  The  residue,  consisting 
of  cotton,  is  washed  free  from  alkali,  dried  at  100°  C.,  and 
weighed. 

To  remove  gum  and  weighting  materials  from  goods  con- 
taining silk,  Richardson  recommends  treatment  of  the  sample 
with  a  cold  2  per  cent  solution  of  caustic  potash;  this  not  only 
removes  any  gum,  but  also  decomposes  any  Prussian  blue 
that  may  be  present  (as  a  bottom  under  the  black  dye),  so 
that  the  iron  may  be  more  easily  removed  by  subsequent  treat- 
ment with  a  i  per  cent  solution  of  hydrochloric  acid.  Metallic 
mordants,  however,  are  difficult  to  remove  in  this  manner, 
and  at  best  they  dissolve  only  imperfectly;  it  is  best  to  calculate 
their  amounts  from  the  quantity  of  ash  left  after  the  ignition 
of  the  sample. 

Oily  matter  (and  also  certain  dyes)  may  be  best  removed 
by  boiling  successively  with  methylated  spirits  and  ether. 
By  evaporation  of  the  solution  so  obtained  the  amount  of  oil 
and  fat  may  be  directly  determined. 

Hohnel  recommends  the  use  of  a  semi-saturated  solution  of 
chromic  acid  (see  p.  148)  for  the  quantitative  separation  of 
mixtures  containing  wool,  cotton,  flax,  true  silk,  and  tussah 
silk.  On  boiling  such  a  mixture  of  fibres  in  this  solution  for 
one  minute,  the  wool  and  true  silk  will  be  completely  dissolved 
leaving  as  a  residue  the  cotton,  flax,  and  tussah  silk. 

Other  methods  given  by  Hohnel  for  the  quantitative  analysis 
of  fabrics  containing  mixtures  of  the  fibres  mentioned  above  are 
as  follows: 

(a)  Any  true  silk  is  first  removed  by  boiling  for  half  a  minute 
in  concentrated  hvdrochloric  acid;  tussah  silk  is  next  removed 


532  THE  TEXTILE  FIBRES 

by  a  longer  boiling  in  the  acid  (three  minutes);  the  residue, 
consisting  of  wool  and  vegetable  fibres,  is  further  separated  in 
the  usual  manner  by  boiling  in  caustic  potash  solution. 

(b)  The  fabric  is  first   boiled   in   caustic  potash   solution, 
which  dissolves  the  wool  and  the  true  silk,  and  leaves  as  a 
residue  (.4)  tussah  silk  and  vegetable  fibre.     A  second  sample 
is  boiled  for  three  minutes  with  concentrated  hydrochloric  acid, 
which  dissolves  both  varieties  of  silk  and  leaves  as  a  residue 
(B)  wool  and  vegetable  fibre.     Residue  A  is  then  boiled  three 
minutes  with  concentrated  hydrochloric  acid,  which  dissolves 
the  tussah  silk  and  leaves  the  cotton  as  a  final  residue.     By 
subtracting  this  amount  from  residue  B  the  amount  of  wool  is 
obtained. 

(c)  A  sample  of  the  fabric  is  boiled  for  one  minute  in  a 
semi-saturated  solution  of   chromic  acid,  which   dissolves   the 
true  silk  and  the  wool,  leaving  as  a  residue  the  tussah  silk  and 
vegetable  fibre.     From  this  residue  the  tussah  silk  is  removed 
by  boiling  for  three  minutes  in  concentrated  hydrochloric  acid, 
leaving  the  vegetable  fibre  as  a  final  residue.     A  second  sample 
is  boiled  for  three  minutes  in  concentrated  hydrochloric  acid, 
which  dissolves  the  silks  and  leaves  the  wool  and  vegetable 
fibre  as  a  residue.     From  this  the  amount  of  wool  can  be  obtained 
either  by  boiling  in  caustic  potash  solution,  or  by  subtracting 
the    cotton    previously    estimated.     Finally,    the    amount    of 
true  silk  may  be  found  by  subtracting  the  sum  of  the  other  con- 
stituents from  the  total  in  the  original  sample. 

5.  Conditioning  of  Textiles.— In  speaking  of  the  hygroscopic 
quality  of  wool,  and  silk  it  was  mentioned  that  these  fibres 
were  capable  of  absorbing  a  considerable  amount  of  moisture, 
and  that  this  amount  varied  within  rather  large  limits,  depend- 
ing upon  the  conditions  of  temperature  and  humidity  of  the 
air  to  which  it  may  be  exposed.  It  may  be  readily  understood 
from  these  facts  that  in  the  buying  and  selling  of  wool  and 
silk  goods  upon  a  basis  of  weight,  the  question  as  to  how  much 
moisture  is  present  becomes  of  great  practical  importance  in 
determining  the  money  value  of  the  operation.  In  England 
and  on  the  continent  of  Europe,  this  fact  has  been  recognized 


ANALYSIS   OF  TEXTILE   FABRICS  AND   YARNS         533 


for  some  time,  and  there  have  been  established  at  the  various 
European  textile  centres  official  laboratories  where  the  per- 
centage of  moisture  in  textile  materials  is  carefully  ascertained, 
and  the  sales  are  based  on  the  actual  amount  of  normal  fibre 
contained  in  the  lot  examined.  These  official  laboratories  * 
are  called  "  conditioning  houses,"  and  the  process  of  determin- 
ing the  amount  of  moisture  is  termed  "  conditioning."  In 
the  conditioning  of  wool  the  operation  is  carried  out  as  follows: 
Representative  samples  are  taken  from  the  lot  under  examina- 
tion; these  are  mixed  together,  and  three  test  samples  of  \  to 
i  pound  each  are  taken.  The  test  sample,  after  being  carefully 
weighed,  is  placed  in  the  conditioning  apparatus  and  dried  to 
constant  weight  at  a  temperature  of  io5°-iio°  C.  (220°  F.). 
This  weight  represents  the  amount  of  dry  wool  fibre  present 
in  the  sample,  the  loss  in  weight  represents  the  amount  of  mois- 
ture the  wool  contained.  The  amount  of  normal  wool  is  obtained 
by  adding  to  the  dry  weight  of  the  wool  the  amount  of  moisture 
supposed  to  be  present  in  the  air-dried  material  under  normal 
conditions  of  humidity  and  temperature.  The  added  amount 
is  termed  "  regain,"  and  is  officially  fixed  by  the  conditioning 
house,  f  This  permissible  percentage  of  regain  varies  with  the 

*  The  first  official  conditioning  house  was  established  at  Lyons  in  1805  for 
the  conditioning  of  silk. 

f  Hartshorne  gives  the  following  table  showing  the  regains  of  worsted  yarns 
for  various  temperatures  and  percentages  of  humidity: 

TABLE  OF  WORSTED  REGAIN  FOR  VARIOUS  TEMPERATURES  AND  PERCENTAGES 

OF  HUMIDITY 


Percentage 

Degrees  Fahrenheit. 

Humiditv. 

SO 

60 

70 

80. 

90. 

100 

40 

12.8 

12.4 

12.0 

n-5 

10.9 

10.4 

50 

14.7 

14-3 

13-8 

13.2 

12.6 

12.  I 

60 

l6.7 

16.1 

15-6 

14.9 

14.4 

13-8 

70 

18.7 

18.0 

17-4 

16.8 

16.2 

15.6 

80 

20.9 

2O.  2 

19.4 

18.7 

18.2 

17.7 

QO 

23-5 

22.7 

21.8 

21  .  I 

20.9 

20.8 

100 

27.1 

26.2 

25-4 

24.8 

24.7 

24.6 

Scheurer  (Bull.  Soc.  Ind.,  Mul.  1900,  Feb.)  conducted  experiments  to  ascertain 


534 


THE  TEXTILE   FIBRES 


form  of  the  manufactured  wool;  the  conditioning  houses  at 
Bradford,  England,  for  instance,  has  established  the  following 
figures : 


Regain 
Per  Cent. 

Direct  Loss, 
Per  Cent. 

Wools  

16 

13  .  79 

Tops  combed  with  oil  
Tops  combed  without  oil 

J9 

i8l 

15-97 

I  C     AT. 

Noils        

14 

12.28 

Worsted  yarns  

i»i 

15-43 

The  system  of  conditioning  adopted  at  Bradford  is  as  fol- 
lows: The  weights  of  the  packages  and  conditions  are  taken 
by  three  persons  independently  on  sensitive  scales  which  are 
adjusted  weekly.  These  scales  have  a  weighing  capacity 
from  one-half  pound  to  ten  tons.  In  making  the  tests  for 
moisture,  the  samples  are  carefully  selected  from  various  parts 
of  the  packages.  The  amount  of  the  material  taken  for  this 
purpose  is  for  wools,  noils,  and  wastes,  about  two  pounds  from 
each  package;  for  tops,  three  balls;  for  yarns  in  hank,  about 
four  pounds  in  1200  pounds;  for  yarns  on  bobbins  or  tubes, 
twenty  to  forty  bobbins  or  tubes,  and  for  yarns  on  cones, 
cheeses,  etc.,  5  to  15  pounds. 

The  standard  regains  and  allowances  are  as  follows: 

Wools  and  waste,  for  moisture,  a  regain  of  16  per  cent,  equal  to  2  ozs.  35  drs. 
per  pound. 

Tops  combed  with  oil,  for  moisture,  a  regain  of  19  per  cent,  equal  to  2  ozs. 
9  drs.  per  pound. 

the  amount  of  water  fixed  by  various  fibres  at  100°  C.  in  an  atmosphere  saturated 
with  steam;  his  results  were  as  follows: 

Fibre  Water  Fixed, 

Previously  Dried  at  100°  C.  Per  Cent. 

Bleached  white  cotton 23 .  o 

Unbleached  linen 27.7 

Unbleached  jute 28.4 

Bleached  silk 36 . 5 

Bleached  and  mordanted  wool 50.0 

According  to  Scheurer,  these  figures  show  that  for  the  textile  fibres  there 
exists  a  fixed  capacity  of  saturation  which  remains  perfectly  constant  in  the  same 
atmosphere  of  steam,  as  soon  as  the  equilibrium  is  once  established. 


ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS         535 

Tops  combed  without  oil,  for  moisture,  a  regain  of  i8j  per  cent,  equal  to 
2  ozs.  *]\  drs.  per  pound. 

Ordinary  noils,  for  moisture,  a  regain  of  14  per  cent,  equal  to  i  oz.  15^  drs. 
per  pound.  Clean  noils,  a  regain  of  16  per  cent,  equal  to  2  ozs.  35  drs.  per  pound. 

Yarns,  worsted,  for  moisture,  a  regain  of  185  per  cent,  equal  to  2  ozs.  7^  drs. 
per  pound. 

Yarns,  cotton,  for  moisture,  a  regain  of  8|  per  cent,  equal  to  i  oz.  4  drs. 
per  pound. 

Yarns,  silk,  for  moisture,  a  regain  of  n  per  cent,  equal  to  i  oz.  95  drs.  per 
pound. 

Cloths,  worsted  and  woolen,  a  regain  of  16  per  cent,  equal  to  2  ozs.  3!  drs. 
per  pound. 

The  conditioning  house  at  Roubaix,  on  the  Continent, 
allows  the  following  percentages  for  regain  on  woolen  materials:* 

Per  Cent. 

Wools I4i 

Tops  f i8i 

Woolen  yarns 17 

The  percentage  of  regain  allowed  at  Bradford  is  considerably 
higher  than  that  which  would  be  allowed  at  most  American 
textile  centres.  The  author  has  found  from  many  conditioning 
tests  at  Philadelphia  that  woolen  yarns  will  average  about  10 
per  cent  of  moisture,  worsted  tops  (in  the  oil)  and  loose  wool 
about  12  per  cent,  and  woven  fabrics  of  wool  about  8  to  9  per 

*  The  International  Congress  at  Turin  (1875)  fixed  the  amount  of  "regain" 
for  different  textile  fibres  as  follows: 

Per  Cent. 

Silk ii 

Wool  (tops) igj 

Wool  (yarn) 17 

Cotton 8£ 

Linen 12 

Hemp 12 

Jute 13! 

New  Zealand  hemp 13$ 

t  The  adoption  of  18.25  Per  cent  regain  as  the  legal  standard  in  France, 
according  to  Persoz  (Rev.  Gen.  Mat.  Col.,  1900,  p.  81)  has  led  to  the  practice 
of  worsted  tops  being  excessively  moistened  before  sale  to  the  spinner.  He 
recommends  a  reversion  to  the  old  standard,  as  he  considers  that  13  per  cent 
is  the  average  amount  of  moisture  in  wool,  and  hence  the  weight  for  normal 
moisture  should  be  found  by  adding  15  per  cent  to  the  dry  weight. 


536 


THE  TEXTILE   FIBRES 


cent.  This  would  correspond  to  a  regain  on  the  dry  weight  as 
follows : 

Per  Cent. 

Woolen  yarns n.i 

Worsted  tops  and  loose  wool 13.6 

Woolen  cloth 9.9 

In  order  to  give  fair  regains  for  commercial  purposes,  the 
author  would  recommend  for  woolen  yarns  a  regain  of  12  per 
cent,  for  tops  and  roving  and  loose  wool,  15  per  cent,  and  for 
wool  cloth,  ii  per  cent.  For  silk  the  regain  allowed  should  be 
ii  per  cent,  and  for  cotton  and  vegetable  fibres  in  general  the 
regain  should  be  7  per  cent. 

The  following  table  shows  the  amount  of  moisture  taken 
up  by  various  fibres  under  different  conditions  of  humidity  and 
at  a  temperature  of  75°  F. 


Per  Cent, 
Relative 
Humidity. 

Per  Cent  Moisture. 

Per  Cent, 
Relative 
Humidity. 

Per  Cent  Moisture. 

Cotton. 

Silk. 

Wool. 

Cotton. 

Silk. 

Wool. 

5 

1.4 

1.8 

2.  2 

55 

6-3 

94 

13-4 

10 

2.4 

3-2 

4.0 

60 

6.7 

9.9 

14.2 

15 

3-0 

4-4 

5-7 

65 

7-3 

iQ-5 

15-0 

20 

3-6 

5-4 

7-i 

70 

7-9 

11.4 

16.0 

25 

3-9 

6.1 

8-3 

75 

8.8 

12.5 

17.1 

30 

4-3 

6-7 

9-4 

80 

9-9 

14.0 

18.6 

35 

4.6 

7-3 

10.4 

85 

11.4 

15-9 

20.5 

40 

5-o 

7.8 

II.  0 

90 

13-6 

18.4 

23.2 

45 

5-3 

8-4 

n.  8 

95 

17-5 

22.  7 

27.0 

50 

5-7 

8.8 

12.6 

In  the  United  States  Government  specifications  for  army 
blankets,  etc.,  of  wool,  a  regain  of  1 1  per  cent  is  allowed. 

The  method  of  calculating  the  amount  of  normal  wool  may 
be  illustrated  by  the  following  example:  A  lot  of  1000  Ibs.  of 
loose  wool  was  submitted  for  conditioning;  ten  samples  of  i  Ib. 
each  were  taken  from  different  parts  of  the  lot;  these  were 
mixed  together  and  three  samples  of  250  gms.  each  were  taken 
for  testing.  On  drying  to  constant  weight  the  three  samples 
lost,  respectively,  (i)  12.25  Per  cent,  (2)  12.30  per  cent,  (3) 
12.22  per  cent,  making  the  loss  12.26  per  cent.  Hence  in  the 


ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS         537 

entire  lot  of  1000  ]bs.  of  wool  there  were  122.6  Ibs.  of  moisture 
or  1000-122. 6  =877.4 Ibs.  of  dry  wool.  The  permissible  amount 
of  regain  in  this  case  was  15  per  cent;  hence  the  amount  of 

normal  wool  would  be  f  877.4 X j +877.4  =  1009  Ibs.  instead 

of  1000  Ibs. 


FIG.  140. — Conditioning  Apparatus. 

The  apparatus  employed  for  the  conditioning  test  is -usually 
one  of  such  a  construction  as  to  be  especially  adapted  for  the 
purpose.  The  form  may  differ  somewhat  in  details  with  dif- 
ferent makers,  but  a  typical  conditioning  oven  may  be  described 
as  follows: 

The  apparatus  consists  of  an  upright  oven  heated  by  a  flame 


538 


THE  TEXTILE   FIBRES 


placed  in  the  lower  chamber.  An  even  temperature  is  main- 
tained by  so  conducting  the  currents  of  heated  air  that  they 
pass  completely  around  the  inner  chamber  or  oven  containing 
the  sample  to  be  tested  (see  Fig.  140).  A  thermometer  project- 


FIG.  141. — Electrically  Heated  Conditioning  Apparatus. 

ing  into  the  oven  from  above  is  employed  for  indicating  the 
temperature,  and  this  may  be  maintained  at  the  desired  point 
by  a  proper  regulation  of  the  supply  of  heat.  The  material 
to  be  conditioned,  in  whatever  form  (as  loose  wool,  yarn,  etc.) 


ANALYSIS  OF  TEXTILE   FABRICS  AND   YARNS         539 

is  placed  in  a  wire  basket  suspended  from  one  arm  of  a  balance 
fixed  outside  and  above  the  oven;  the  weight  of  the  basket 
and  its  contents  is  counterpoised  by  placing  definite  weights 
on  a  scale-pan  suspended  from  the  other  arm  of  the  balance. 
As  the  material  diminishes  in  weight  through  the  volatilization 
of  its  moisture,  the  loss  is  noticed  from  time  to  time  by  removing 
the  necessary  weights  from  the  scale-pan  in  order  to  restore 
the  equilibrium  of  the  balance.  When  the  weight  becomes 
constant  after  heating  at  110°  C.,  the  total  loss  is  recorded,  and 
this  figure  represents  the  amount  of  moisture  which  was  originally 
present  in  the  material  tested.  The  balance  is  usually  enclosed 
in  a  suitable  case  in  order  to  protect  it  from  draughts  of  air 
whereby  its  sensibility  would  be  impaired. 

6.  Calculations  Involved  in  Conditioning. — In  the  con- 
ditioning of  wool  (or  of  any  other  textile  material),  there  are 
certain  calculations  necessary  which  it  may  be  advisable  at 
this  point  to  explain.  The  two  principal  calculations  to  be 
made  involve  the  determination  of  the  percentage  of  moisture 
based  on  the  weight  of  the  material  as  taken  for  the  test  (that 
is,  on  its  moist  weight),  and  then  the  determination  of  the 
conditioned  weight  of  the  material  based  on  a  definite  percentage 
allowance  of  "regain,"  this  percentage  being  calculated  on  the 
dry  weight  of  the  material.  The  different  problems  in  con- 
ditioning will  now  be  considered.* 

(i)  If  a  weight  (w)  of  material  after  drying  shows  a  weight 
(a),  what  percentage  (x)  of  moisture  does  it  contain? 

w  —  a  =  loss  in  weight  on  drying  =  moisture. 
w 


w  —  a 


Xioo  =  x,  per  cent  of  moisture. 


(2)  If  a  quantity  of  material  of  weight  (w)  contains  x  per 
cent  of  moisture,  what  is  its  dry  weight  (a)? 


(  i  — 


— \ 

IOO/' 


*  See  Person,  Essai  des  Mailer es  Textiles. 


540 


THE  TEXTILE  FIBRES 


(3)  If  from  a  weight  (W)  of  material  there  is  taken  a  sample 
of  weight  (w)  and  the  dried  weight  of  this  is  found  to  be  (a), 
what  will  be  the  conditioned  weight  (C)  of  the  material,  allowing 
a  regain  of  (R)  per  cent? 

The  dry  weight  (^4)  of  the  entire  material  will  be 


A-WX-, 


and  the  conditioned  weight  will  be 


JL] 

100 1' 


(4)  A  substance  is  conditioned  with  a  regain  of  (R)  per  cent, 
what  percentage  of  moisture  (x)  does  it  contain? 
We  have  the  proportion 


loo+R     100 


R 


x 


therefore 


ipoR 
loo+R 


The  following  table  shows  the  percentage  of  moisture  in 
any  material  corresponding  to  a  definite  percentage  of  regain. 


Per  Cent  Regain. 

Per  Cent  of  Moisture. 

Per  Cent  Regain. 

Per  Cent  of  Moisture. 

5 

4.76 

12 

10.71 

6 

5-66 

12.5 

II.  II 

7 

6-54 

13 

11.50 

7-5 

6.98 

14 

12.28 

8 

7.41 

15 

I3-04 

8-5 

7-83 

16 

13-79 

9 

8.26 

17 

14-53 

10 

9.09 

18 

I5-25 

ii 

9.91 

19 

15-97 

20 

16.67 

ANALYSIS  OF  TEXTILE   FABRICS  AND  YARNS         541 

(5)  If  the  material  contains  (x)  per  cent  of  moisture,  what 
will  be  the  corresponding  percentage  of  regain  (R)? 

This  is   the   reverse   of   the   previous   problem.     We   have 


:   ' 


=     -. 

100  —  X 

The  following  table  shows  the  percentage  of  regain  of  any 
material  corresponding  to  a  definite  percentage  of  moisture:* 


Per  Cent  of  Moisture. 

Per  Cent  Regain. 

Per  Cent  of  Moisture. 

Per  Cent  Regain. 

5 

5.26 

13 

14.94 

6 

6.38 

14 

16.28 

7 

7-53 

15 

I7-6S 

8 

8.70 

16 

I9-OS 

9 

9.89 

17 

20.48 

10 

ii.  ii 

18 

21-95 

ii 

12.36 

iQ 

23.46 

12 

13.64 

20 

25.00 

*  Hartshorne  has  worked  out  some  mathematical  relations  concerning  the  laws 
of  regain  of  moisture  in  cotton  and  worsted.  His.  general  conclusions  are  as 
follows:  (i)  The  general  law  for  cotton  and  worsted  (and  probably  for  any  other 
textile  fibre)  may  be  expressed  by  the  formula, 


in  which  H  represents  any  given  per  cent  of  relative  humidity.  R  the  regain  at 
any  absolute  temperature  T,  K  a  variable  coefficient  depending  upon  both  H, 
R,  and  T  in  such  a  way  that  for  H=i,  the  product  KRT3  is  a  constant  quantity 
represented  by  the  number  5771.44X108.  This  constant  number,  5771.44,  is 
the  weight  in  grains  of  a  cubic  foot  of  water  vapor  at  any  temperature  multiplied 
by  the  corresponding  absolute  temperature,  expressed  in  degrees  Fahrenheit, 
divided  by  the  maximum  elastic  force  of  water  vapor  at  that  temperature, 
expressed  in  inches  of  mercury.  (2)  For  any  given  temperature  the  relations  of 
values  of  R  to  the  variable  K,  for  both  worsted  and  cotton,  is  expressed  by  a 
hyperbolic  equation  differing  for  each  substance.  (3)  For  any  other  temper- 
ature the  law  for  worsted  is:  For  the  same  humidity  the  squares  for  the  regains 
at  different  temperatures  are  to  each  other  inversely  as  the  cubes  of  the  corre- 
sponding absolute  temperatures.  (4)  The  law  for  cotton  is:  For  the  same 
humidity  the  first  po.wers  of  the  regains  at  different  temperatures  are  to  each 
other  inversely  as  the  first  powers  of  the  corresponding  absolute  temperatures. 


542  THE  TEXTILE  FIBRES 

(6)  If  a  material  is  required  to  possess  a  definite  conditioned 
weight  (C),  what  percentage  of  regain  (R)  must  be  applied  to 
the  dry  weight  (a)? 

We  have  the  proportion 


100 


therefore 


=  ioo . 


(7)  If  the  dry  weight  (a)  of  any  material  is  given,  what 
quantity  of  water  (q)  would  it  have  to  absorb  in  order  to  con- 
tain (x)  per  cent? 

We  have  the  proportion 


loo  —  x    a 


X          q 
therefore 


ax 


100  —  x 


The  weight  (W)  of  the  material  after  absorbing  the  moisture 
would  be 


or 

looa 


W  = 


IOO  —  X 


(8)  If  the  dry  weight  (a)  of  a  material  is  given,  what  would 
be  its  conditioned  weight  (C),  allowing  (R)  percentage  of  regain? 
We  have  in  this  case 


ANALYSIS  OF  TEXTILE  FABRICS   AND   YARNS        543 

(9)  If  the  conditioned  weight  (C)  of  a  material  is  given  with 
a  percentage  of  regain  (R),  what  is  its  dry  weight  (a)? 
From  the  previous  formula  we  have 

looC 


"ico+tf- 

(10)  If  the  percentage  of  moisture  (x)  is  known  in  a  material, 
what  will  be  the  conditioned  weight  (C),  allowing  a  regain  of 
(R)  per  cent? 

The  dry  weight  (a)  will  be 


/        x  \ 
a(  i  — -I. 

\       loo/ 


Therefore   the   conditioned   weight  with   (R)   per   cent   regain 
will  be 

C  =  a(i   -—}(i  -~] 
V      loo/V     ioo/ 

(n)  If  the  original  weight  (W)  of  a  material  is  known  and 
also  its  conditioned  weight  (C),  what  percentage  difference  in 
weight  (D)  would  there  be  between  the  original  weight  and  the 
conditioned  weight? 

We  have  the  proportion 

W       ioo 
W-C~  D  ' 

therefore 

ioo(W-C) 


D  = 


W 


There  would  be  a  gain  or  loss  by  conditioning  according  to 
whether  (W)  is  greater  or  less  than  (C). 


544  THE  TEXTILE  FIBRES 

(12)  If  the  conditioned  weight  (C)  of  a  material  is  given 
and  also  its  percentage  difference  (D)  on  conditioning,  find  the 
original  weight  (W)  of  the  substance. 

From  the  previous  formula  we  have 


w     IOOC 


loo-D' 

(13)  If  the  original  weight  (W)  of  a  material  is  known  and 
also  the  percentage  difference   (D)   on  conditioning,  find   the 
conditioned  weight  (C). 

From  the  previous  formula  we  have 

W(ioo-D) 

\s  — 

TOO 

(14)  If  a  material  contains  (x)  per  cent  of  moisture,  calcu- 
late the  difference  (d)  between  its  original  weight  (W)  and  its 
conditioned  wreight  (C)  with  a  regain  of  (R)  per  cent. 

This  difference  is 

d  =  W-C, 
and  from  the  formula  under  (10)  we  have 


hence 

W[(ioo+R)x-iooR] 


d 


10,000 


If  (W)  in  this  formula  is  taken  as  equal  to  100,  the  expression 
becomes  simplified  to 


IOO 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS        545 

According  to  the  value  of  (x)  this  difference  will  be  positive  or 
negative;  that  is  to  say,  the  material  will  lose  or  gain  by  con- 
ditioning. 
If 

looR 
x  is  greater  than 

there  will  be  a  loss. 
If 

looR 


x  = 


100  +R 


the  fibre  will  be  in  its  conditioned  state. 
Finally,  if 

looR 


x  is  less  than 


loo+R 


the  material  will  gain  in  weight  by  conditioning. 

(15)  If  the  difference  (d)  between  the  original  weight  (W) 
of  a  material  and  its  conditioned  weight  (C)  at  a  regain  oi(R) 
per  cent  is  known,  find  the  percentage  of  moisture  (x)  in  the 
material. 

This  is  the.  reverse  of  the  preceding  problem  and  may  be 
solved  by  taking  the  reciprocal  of  the  formula  for  (d),  as  follows: 

ioo(WR+iaod) 
W(ioo+R)     ' 

If  we  take  the  original  weight  as  equal  to  100  and  call  (D)  the 
corresponding  difference,  the  expression  becomes 

_  ioo(R+D) 
loo+R    ' 

It  is  necessary  to  remember  in  these  formulas  that  the  value 
of  (d)  or  (D)  is  positive  only  if  the  original  weight  is  greater 
than  the  conditioned  weight;  if  the  contrary  is  the  case,  the 
difference  will  be  of  a  negative  value.  For  example,  a  sample 


546  THE  TEXTILE  FIBRES 

of  wool  loses  2  per  cent  on  conditioning  at  15  per  cent  regain; 
hence  it  contains 


100(1 

—  =14.7  per  cent  moisture, 
100+15 

whereas  if  it  gains  2  per  cent  in  weight  by  conditioning,  we 
have 

100(15  —  2) 

—  =  11.3  per  cent  moisture. 
100+15 

(16)  A  sample  of  material  shows  a  difference  in  weight  of 
(Z>)  per  cent  on  conditioning  at  (R)  per  cent  regain,  what 
difference  (D')  would  there  be  if  conditioned  at  a  regain  of 
(R')  per  cent? 

If  we  call  the  dry  weight  (a\  then 


I+--> 

IOO/' 

/        /?'  \ 

Z/  =  ioo-a(T  + — ). 
V       loo/ 


Hence,  by  eliminating  (a), 'we  have 

(100  +R')D-  ioo(Rf  -R) 


D' 


loo+R 


This  problem  will  often  arise  in  practice  where  two  different 
sets  of  regains  are  to  be  allowed.  For  example,  a  sample  of 
wool  conditioned  at  a  regain  of  15  per  cent  loses  0.4  per  cent  in 
weight,  how  much  would  it  lose  if  the  regain  allowed  was  17 
per  cent? 

n,     (117X0.4) -(100X2) 

D  ' —  —  —  =  —1.3  per  cent; 

that  is  to  say,  the  fibre  would  gain  1.3  per  cent  in  weight. 

(17)  A  sample  of  material  on  conditioning  at  a  regain  of 
(R)  per  cent  shows  a  loss  of  (D)  per  cent,  what  regain  would 
have  to  be  adopted  in  order  that  the  loss  may  be  (ZX)  per  cent? 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS        547 
From  the  previous  formula  we  have 

,     ioo(D+R)-D'(ioo+R) 
loo-D 

(18)  If  the  conditioned  weight  (C)  at  a  regain  of  (R)  per 
cent  is  known,  calculate  the  conditioned  weight  (C')  at  a  regain 
of  (R')  per  cent. 

From  the  formula  under  (8)  we  have 

C      loo+R 
C'~ioo+#'; 
hence 

C'=CIOO+R' 


(19)  In  a  textile  material  consisting  of  two  kinds  of  fibres, 
if .  the  percentage  conditioned  amounts  of  the  two  fibres  are 
known,  (C)  and  (C),  and  their  respective  regains  are  (R)  and 
(Rf) ,  what  will  be  the  average  regain  (r)  and  the  average  amount 
of  moisture  (x)  in  the  mixture? 

If  (C)  and  (C')  are  the  conditioned  weights  of  the  two  fibres, 
their  dry  weights  (-4)  and  (A')  would  be 

icoC  ,       looC" 

A  = rr;.     and    A  = 


the  average  moisture  would  be 

/  looC         looC"  \ 

X=IOO—  [-       ~7~^-r~      r~B// 

\ioo+R     loo+R  I 
hence 

[1C  C' 

_  (  • 

\ioo-\-R 

The  average  regain  would  be 

i  oox 

100  —  X' 


548  THE  TEXTILE  FIBRES 

For  example,  suppose  we  have  conditioned  a  yarn  composed  of 
65  per  cent  of  wool  and  35  per  cent  of  cotton,  with  respective 
regains  of  15  and  7  per  cent.  Then 


x  =  ().6  per  cent  moisture, 

r  =  10.6  per  cent  average  regain. 

(20)  In  a  textile  of  mixed  fibres  if  the  proportion  (P)  and 
r)  of  the  two  fibres  is  known  on  the  dry  weight  (A),  together 
with  the  moisture  (x)  lost  on  drying,  what  would  be  the  con- 
ditioned weight   (C)   of  the  material,   allowing   (R)   and   (R') 
respectively  as  the  regains  for  the  two  fibres? 
We  have 

P 

—  A  —  amount  of  first  fibre, 
100 


P' 

— A  =  amount  of  second  fibre, 
100 


and 


IOO 

P'A 

IOO 


- )  +—  -    =  conditioned  weight  of  first  fibre. 

IOO/        IOO 

'A     R'  \     P' A 

—  X —  )+ =  conditioned  weight  of  second  fibre. 

X)         IOO/        IOO 

Adding  these  two  terms  gives  us 

(PR-\-P'R  \ 
1 4- —  I  =  conditioned  weight  of  entire  material. 
10000     / 

For.  example,  suppose  a  yarn  contains  60  per  cent  of  wool  and 
40  per  cent  of  cotton  on  a  dry  weight  of  85  pounds,  allowing 
respective  regains  of  15  and  7  per  cent,  what  would  be  the  con- 
ditioned weight  of  the  yarn? 


ANALYSIS   OF  TEXTILE   FABRICS  AND   YARNS         549 


TABLE  SHOWING  THE  CONDITIONED  WEIGHT  OF  100  POUNDS  or  ANY  MATERIAL 
WITH  REGAINS  OF  7,  n,  AND  15  PER  CENT,  CONTAINING  DIFFERENT  AMOUNTS 
OF  MOISTURE 


Per  Cent, 
Moisture. 

Conditioned  Weight,  Regains. 

Per  Cent, 
Moisture. 

Conditioned  Weight,  Regains. 

Per  Cent. 

ii                  IS 
Per  Cent.   Per  Cent. 

Per  Cent. 

ii 
Per  Cent. 

Per  Cent. 

5  ° 

101.65 

105-45 

109.25 

9-0 

97-37 

IOI  .OI 

104.65 

.1 

101.54 

105-34 

109.14 

.1 

97.26 

100.90 

104-53 

.2 

101  .44 

105-23 

109.02 

.2 

97.16 

100.79 

104.42 

•3 

101.33 

IO5  .  12 

108.91 

•3 

97-05 

100.68 

104.30 

•4 

101.22 

105  .01 

108.  79 

•4 

96.94 

100.57 

104.19 

•5 

IOI  .  12 

104.90 

108.68 

•5 

96.84 

100.46 

104.07 

.6 

101  .01 

•IO4.  78 

108.56 

.6 

96.73 

100.34 

103.96 

•  7 

100.90 

104.67 

108.45 

•7 

96.62 

100.23 

103  .  84 

.8 

I00.80 

104.56 

108.33 

.8 

96.51 

TOO.  12 

103  -  73 

•  9 

IOO.69 

104-45 

IO8.  22 

•9 

96.41 

IOO.OI 

103.61 

6.0 

100.58 

104-34 

108.  10 

IO.O 

96.30 

99.90 

103  .  50 

.1 

100.48 

104.23 

107.99 

.1 

96.19 

99-79 

103-38 

.2 

100.37 

104.  12 

107.87 

.2 

96.09 

99.68 

103.27 

•3 

100.  26 

104.01 

107.76 

•3 

95.98 

99-57 

103.16 

•4 

100.15 

103.90 

107.64 

•  4 

95.87 

99.46 

103.04 

•5 

100.05 

103  -  79 

107.53 

•5 

95-77 

99-34 

102.93 

.6 

99  94 

103.67 

107.41 

.6 

95.66 

99-23 

102.81 

-7 

99-83 

103.56 

107.30 

•7 

95-55 

99.12 

102.70 

.8 

99.72 

103-45 

107.  18 

.8 

95-45 

99-01 

102.58 

•9 

99.62 

103-34 

107.07 

•9 

95-34 

98.90 

102.47 

7-0 

99-51 

103.23 

106.95 

II.  0 

95.23 

98  .  79  ' 

102.35 

.1 

99.40 

103.12 

106  .  84 

.1 

95   12 

98.68 

102.24 

.2 

99-30 

103.01 

106.72 

.2 

95.02 

98.57 

102.  12 

•3 

99.19 

102.90 

106.61 

•3 

94.91 

98.46 

IO2.OI 

•4 

99-08 

102.79 

106.49 

•4 

94.81 

98.35 

IOI  .89 

•5 

98.98 

102.68 

106.38 

•5 

94-70 

98-23 

ioi  .78 

.6 

98-87 

102.56 

1  06  ..  26 

.6 

94-59 

98.12 

ioi  .66 

•7 

98.76 

102.45 

106.15 

•  7 

94.48 

98.01 

101.55 

.8 

98.66 

102.34 

106.03 

.8 

94-37 

97.90 

101.43 

•9 

98.55 

102.23 

105.92 

•9 

94-27 

97-79 

101.32 

8.0 

98.44 

102.12 

105.80 

12.0 

94.16 

97.68 

IOI  .  2O 

.1 

98.34 

102.01 

105.69 

.1 

94-05 

97-57 

ioi  .08 

.2 

98.23 

ioi  .90 

105-57 

.  2 

93-95 

97.46 

100.97 

•3 

98.12 

101.79 

105.46 

•3 

93-84 

97-35 

100.85 

•  4 

98.01 

101.68 

105-34 

•4 

93  •  73 

97-24 

100.74 

•  5 

97.90 

101.57 

105.23 

•5 

93.62 

97.12 

100.62 

.6 

97.80 

101.45 

105.11 

.6 

93-52 

97.01 

100.51 

•7 

97.69 

101.34 

105.00 

•  7 

93-41 

96.90 

100.39 

.8 

97.58 

101.23 

104  .  88 

.8 

93-30 

96.79 

100.  28 

•9 

97.48 

IOI  .  12 

104.77 

•9 

93.19 

96.68 

100.  16 

550 


THE  TEXTILE  FIBRES 


TABLE  SHOWING  THE  CONDITIONED  WEIGHT — (Continued) 


Per  Cent. 
Moisture. 

Conditioned  Weight,  Regains. 

Per  Cent, 
Moisture. 

Conditioned  Weight,  Regains. 

Per  Cent. 

II 
Per  Cent. 

Per  Cent. 

7 
Per  Cent. 

ii 
Per  Cent. 

Per  Cent. 

13-0 

93-09 

96.57 

100.05 

17.0 

88.  81 

92.13 

95-45 

.1 

92.98 

96.46 

99-94 

I 

88.71 

92.02 

95-34 

.  2 

92.88 

96.35 

99.82 

t 

88.60 

91.91 

95-22 

•3 

92.77 

96-24 

99.71 

•3 

88.49 

91.80 

95-n 

•4 

99.66 

96.13 

99-59 

•4 

88.38 

91.69 

94  99 

•5 

92.55 

96.01 

99.48 

•5 

88.28 

91-57 

94.88 

.6 

92.45 

95.90 

99-36 

.6 

88.17 

91.46 

94.76 

•  7 

92-34 

95-79 

99-25 

-7 

88.06 

91-35 

94.65 

.8 

92.23 

95-68 

99   13 

.8 

87-95 

91.24 

94-53 

•9 

92.  12 

95-57 

99.02 

•9 

87-85 

9J-i3 

94.42 

14.0 

92.02 

95-46 

98.90 

18.0 

87.74 

91  .02 

94  •  30 

.1 

91.91 

95-35 

98.78 

.  i 

87-63 

90.91 

94.18 

.2 

9I.8l 

95-24 

98.67 

.2 

87.52 

90.80 

94-07 

•3 

91.70 

95-13 

98-56 

"2 

87.42 

90.69 

93-96 

•4 

91-59 

95-02 

98.44 

•4 

87.31 

90.58 

93.84 

•  5 

91.49 

94-90 

98.33 

-5 

87  .  21 

90.46 

93-73 

.6 

91.38 

94-79 

98.21 

.6 

87.  10 

90.35 

93.61 

•7 

91.27 

94.68 

98.10 

•  7 

86.99 

90.24 

93-50 

.8 

9I.I6 

94-57 

97.98 

.8 

86.88 

90.13 

93-38 

•9 

9I-05 

94.46 

07-87 

•9 

86.78 

90.02 

93-27 

15.0 

90.95 

94-35 

97-75 

19.0 

86.67 

89.91 

93-15 

.  i 

90.84 

94.24 

97.64 

.1 

86.56 

89.80 

93-04 

.2 

90.74 

94-13 

97-52 

.  2 

86.45 

89.69 

92.92 

•  3 

90.63 

94-02 

97-41 

•3 

86.35 

89-58 

92.81 

•4 

90.52 

93  9i 

97.29 

•4 

86.24 

89-47 

92.69 

•  5 

90.42 

93-79 

97.18 

-     -5 

86.13 

89-36 

92.58 

.6 

90.31 

93-68 

97.06 

.6 

86.02 

89.24 

92.46 

•  7 

9O.  20 

93-57 

96.95 

•7 

85-92 

89.13 

92.35 

.8 

90.09 

93-46 

96.83 

.8 

85.81 

89.02 

92-23 

•9 

89-98 

93-35 

96.72 

•9 

85-71 

88.91 

92.  12 

16.0 

89.88 

93   24 

96.60 

20.  o 

85.60 

88.80 

92.OO 

.1 

89.77 

93-13 

96.48 

.1 

85-49 

88.69 

91.88 

.2 

89-67 

93-02 

96.37 

.  2 

85-38 

88.58 

91.77 

.3 

89.56 

92.91 

96.  26 

•3 

85.28 

88.47 

91  .66 

•  4 

89-45 

92.80 

96.14 

•4 

85-I7 

88.36 

91-54 

•5 

89.34 

92.68 

96.03 

-5 

85.06 

88.25 

91-43 

.6 

89.24 

92-57 

95-9T 

.6 

84-95 

88.13 

9!-3i 

•  7 

89.13 

92-46 

95.80 

•  7 

84.85 

88.02 

91  .  20 

.8 

89.02 

92.35 

95-68 

.8 

84.74 

87.91 

91.08 

•9 

88.92 

92.24 

.95-57 

•9 

84.63 

87.80 

90-97 

21  .O 

84.53 

87.69 

90.85 

ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS         551 

7.  Analysis  of  Weighting  in  Silk  Fabrics. — The  practice  of 
adding  to  the  weight  of  silk  in  the  dyeing  and  finishing  opera- 
tions has  become  so  common  that  it  is  frequently  desirable  to 
ascertain  in  a  sample  of  silk  goods  the  amount  of  true  fibre 
present  and  the  amount  and  character  of  weighting.*  Black- 
dyed  silk  is  especially  liable  to  contain  a  very  large  amount  of 
weighting  materials;  sometimes  the  degree  of  weighting  may 
reach  as  high  as  400  per  cent  or  even  more.  Colored  silks  are 
usually  not  weighted  to  such  a  great  extent,  but  they  will  fre- 
quently be  found  also  to  contain  considerable  adulteration. 
Black-dyed  silks  are  mostly  loaded  with  Prussian  blue  and  iron 
tannate,  the  latter  being  obtained  by  immersing  the  silk  in  a 
solution  of  pyrolignite  or  nitrate  of  iron,  and  subsequently 
in  a  solution  of  cutch  or  other  tannin.  Colored  silks  are  prin- 
cipally weighted  with  tin  phosphate  obtained  by  treating  the 
material  with  solutions  of  tin  perchloride  and  sodium  phosphate. 
Sometimes  light-colored  silks  are  also  weighted  with  sugar, 
magnesium  chloride,  etc.  Such  materials  are  soluble  in  warm 
water,  and  hence  their  use  is  easily  detected. 

A  convenient  test  which  is  frequently  applicable  to  detect 
weighting  is  to  ignite  the  silk  fibre;  if  it  is  heavily  weighted 
it  will  not  inflame,  but  gradually  smolder  away  and  leave  a 
coherent  ash  retaining  the  original  form  of  the  fibre. 

In  general  the  substances  which  may  be  present  as  weighting 
materials  are  iron,  as  ferrocyanide  or  tannate;  tin,  as  tannate, 
tungstate,  phosphate,  silicate,  or  hydroxide;  chromium  com- 
pounds; the  sulphates  or  chlorides  of  sodium,  magnesium,  and 
barium;  organic  matters,  such  as  sugar,  glucose,  gelatin, 
tannins,  etc. 

The  following  method  is  one  which  has  been  recommended 
for  the  qualitative  analysis  of  weighting  materials  on  silk :  t 
Substances  that  are  easily  soluble,  such  as  sugar,  glucose, 

*Lewitzki  (Farber.-Zeit.,  1911,  p.  42)  calls  attention  to  the  fact  that  raw  silk 
is  sometimes  found  to  be  adulterated  with  weighting  materials.  These  consist 
chiefly  of  soap,  fat,  and  glycerin  and  some  silk  is  also  colored  with  methyl  orange. 
Such  silk  had  obviously  been  reeled  from  all  sorts  of  old  cocoons  and  then  tinted 
with  methyl  orange  to  give  it  the  appearance  of  a  uniform  product. 

t  Silbermann,  Chem.  Zeit.,  vol.  18,  p.  744. 


552  THE  TEXTILE   FIBRES 

glycerol,  magnesium  salts,  etc.,  are  estimated  directly  by  boil- 
ing the  silk  with  water  and  testing  the  extract  with  Fehling's 
solution,  etc.*  From  2  to  3  gms.  of  the  silk  are  ignited  and  the 
ash  is  tested  for  tin  (which  may  be  present  in  the  fibre  as  basic 
chloride  and  stannic  acid),  chromium,  iron,  etc. 

These  metals  may  be  tested  for  in  the  ash  in  the  following 
manner:  Moisten  with  a  few  drops*  of  nitric  acid  and  re-ignite 
in  order  to  be  certain  that  all  carbon  is  removed.  Treat  the 
residue  with  eight  to  ten  drops  of  strong  sulphuric  acid;  and 
gently  heat  until  fumes  are  evolved;  allow  to  cool  and  boil 
with  water,  dilute  to  about  100  cc.  with  water,  and  then  pass 
hydrogen  sulphide  gas  through  the  liquid;  filter,  and  examine 
the  solution  and  precipitate  as  follows:  The  aqueous  solution 
may  contain  zinc  or  iron;  add  a  few  drops  of  bromin  water 
to  remove  excess  of  hydrogen  sulphide  and  to  oxidize  any  iron 
present  to  the  ferric  condition;  boil,  then  add  ammonia  in  slight 
excess;  boil  again,  and  filter;  if  there  is  a  precipitate,  it  may 
contain  iron;  if  so,  it  should  be  brown  in  color;  dissolve  in  a 
little  hydrochloric  acid  and  add  a  few  drops  of  a  solution  of 
potassium  ferrocyanide;  a  blue  color  will  confirm  the  presence 
of  iron.  The  filtrate,  which  may  contain  zinc,  should  be  heated 
to  the  boil,  and  a  few  drops  of  potassium  ferrocyanide  solution 
added;  a  white  precipitate  will  indicate  zinc.  The  original 

*  Fehling's  reagent  is  an  alkaline  solution  of  copper  sulphate  containing 
potassium  tartrate.  It  is  prepared  in  the  following  manner:  34.639  gms.  of 
pure  crystallized  copper  sulphate  are  dissolved  in  about  256  cc.  of  water;  173  gms. 
of  Rochelle  salt  (sodium  potassium  tartrate)  are  dissolved  in  the  same  quantity 
of  water;  60  gms.  of  caustic  soda  are  similarly  dissolved.  The  three  solutions 
are  then  mixed,  and  the  mixture  diluted  to  iooo  cc.  with  water.  The  reagent 
is  employed  as  follows:  10  cc.  of  the  solution  are  diluted  with  40  cc.  of  water 
and  brought  to  a  boil;  there  is  then  added  a  portion  of  the  solution  to  be 
tested  for  sugar  (or  glucose)  which  has  previously  been  boiled  with  a  small 
quantity  of  dilute  hydrochloric  acid.  If  sugar  is  present,  the  Fehling's  solution 
will  be  decolorized  and  a  bright  red  precipitate  of  cuprous  oxide  will  be  thrown 
down.  This  test  may  be  made  quantitative  by  using  a  known  quantity  of  sugar 
solution,  filtering  off  the  cuprous  oxide,  igniting,  and  finally  weighing  as  copper 
oxide  (CuO).  In  order  to  determine  the  amount  of  sugar  (or  glucose)  corre- 
sponding to  this  latter,  reference  should  be  made  to  tables  constructed  by  Allihn 
showing  the  proper  equivalents  of  sugar  and  glucose  for  the  amounts  of  copper 
oxide  determined. 


ANALYSIS  OF  TEXTILE   FABRICS  AND  YARNS         553 

precipitate  produced  by  the  treatment  with  hydrogen  sulphide 
is  next  examined.  This  may  contain  lead,  tin,  or  copper; 
it  is  fused  for  ten  minutes  in  a  porcelain  crucible  with  2  gms. 
of  a  mixture  of  potash  and  soda  ash  together  with  i  gm.  of 
sulphur.  On  cooling,  the  mass  is  boiled  with  water  and  filtered. 
The  residue  may  contain  lead  and  copper;  it  is  boiled  with 
strong  hydrochloric  acid  and  a  few  drops  of  bromin  water  are 
added  for  the  purpose  of  completely  oxidizing  any  copper  sul- 
phide present;  filter  if  necessary,  and  add  to  the  filtrate  an 
excess  of  ammonia,  when  a  blue  color  will  indicate  presence 
of  copper.  Acidulate  the  liquid  with  acetic  acid  and  divide 
into  two  portions:  to  the  first  add  a  few  drops  of  a  solution  of 
potassium  bichromate;  a  yellow  precipitate  will  confirm  the 
presence  of  lead;  to  the  other  add  a  few  drops  of  a  solution 
of  potassium  ferrocyanide,  when  a  brown  precipitate  or  colora- 
tion will  indicate  presence  of  copper.  The  filtrate  from  the 
residue  after  the  above  fusion  is  acidulated  with  acetic  acid, 
when  a  yellow  precipitate  of  stannic  sulphide  will  indicate  the 
presence  of  tin.  The  latter  test  may  be  confirmed  by  dissolving 
the  precipitate  of  stannic  sulphide  in  hydrochloric  acid  and 
bromin  water.  The  filtered  solution  is  then  boiled  with  small 
pieces  of  metallic  iron  to  reduce  the  tin;  the  liquid  is  diluted 
and  filtered  and  a  drop  of  mercuric  chloride  solution  is  added, 
when  a  white  or  gray  turbidity  will  be  produced  if  tin  is  present. 

Fatty  matters,  wax,  and  paraffin  are  detected  by  extraction 
with  ether  or  benzene. 

Japan  tram  silk  is  frequently  weighted  with  fatty  substances. 
The  normal  amount  of  fat  in  raw  silk  never  exceeds  0.06  per 
cent.  A  direct  determination  of  the  fatty  matters  may  be 
made  by  treating  5  gms.  of  the  silk  sample  in  a  stoppered  flask 
with  pure  benzene  three  or  four  times  successively,  using  about 
60  cc.  of  the  solvent  each  time  and  allowing  it  to  act  from  two 
to  four  hours  with  frequent  shaking.  The  several  portions  of 
benzene  are  brought  together  and  evaporated  to  dryness  in  a 
tared  dish  and  the  fatty  residue  is  weighed.  Another  method 
is  to  extract  with  ether  in  a  Soxhlet  apparatus. 

To  detect  mineral  weighting  the  silk  is  soaked  in  warm 


554  THE  TEXTILE  FIBRES 

dilute  hydrochloric  acid  (i :  2)  after  complete  removal  of  fatty 
matters;  if  the  fibre  is  almost  decolorized  by  this  treatment, 
only  a  slight  yellow  tint  remaining,  while  the  solution  assumes 
a  deep  brownish  color  not  changed  to  violet  by  addition  of 
lime-water,  it  is  safe  to  conclude  that  the  silk  has  been  weighted 
by  alternate  passages  through  baths  of  iron  salts  and  tannin. 
The  yellow  color  of  the  fibre  is  due  to  a  residuum  of  tannin,  and 
the  precise  shade  (from  greenish  to  brownish  yellow)  enables 
some  idea  to  be  formed  as  to  the  nature  of  the  tanning  material 
used  (sumac,  divi-divi,  cutch,  etc.).  Decolorization  of  the 
fibre,  the  acid  extract  being  pink,  and  changing  to  violet  by 
lime-water,  indicates  a  logwood  black.  If  the  fibre  retain  a 
deep  greenish  tint  and  the  solution  be  yellow  and  unaffected 
by  lime-water,  the  black  is  dyed  on  a  bottom  of  Prussian  blue. 
If  the  latter  has  been  produced  during  the  final  stage  of  dyeing, 
this  will  be  shown  by  its  solubility  in  the  acid.  A  green  fibre 
and  pink  solution,  changing  to  violet  on  addition  of  lime-water, 
indicate  a  logwood  black-dyed  on  a  bottom  of  Berlin  blue.  In 
the  hydrochloric  acid  solution,  such  metals  as  lead,  tin,  iron, 
chromium,  and  aluminium  may  be  determined.  Blacks  pro- 
duced by  artificial  dyes  on  a  bottom  of  iron-tannin  or  iron- 
blue-tannin  may  be  recognized  by  the  coloration  imparted  to 
acid  and  caustic  soda  solutions.  With  blacks  produced  solely 
with  coal-tar  dyes,  treatment  with  a  hydrochloric  acid  solution 
of  stannous  chloride  does  not  affect  anilin  and  alizarin  blacks; 
naphthol  black  is  changed  to  reddish  brown,  and  wool  black 
becomes  yellowish  brown.  Tannin  materials  in  general  may 
be  extracted  by  alkalies,  and  subsequently  precipitated  and 
distinguished  by  ferric  acetate.  To  remove  the  whole  of  the 
weighting  material  and  the  dye,  the  silk  should  be  boiled  with 
acid  potassium  oxalate,  washed  with  dilute  hydrochloric  acid, 
and  finally  treated  with  soda  solution.  When  iron  and  tin  are 
both  present  in  the  fibre,  it  is  best  to  first  extract  the  tin  by 
treatment  with  a  solution  of  sodium  sulphide. 

Persoz  recommends  in  testing  for  tin  weighting  on  dark- 
colored  and  black  silks  to  boil  the  sample  for  a  few  minutes  in 
concentrated  hydrochloric  acid.  Then  dilute  and  filter  the 


ANALYSIS  OF  TEXTILE   FABRICS  AND   YARNS          555 

acid,  and  pass  hydrogen  sulphide  into  it,  when  a  yellow  pre- 
cipitate (SnS)  would  indicate  the  presence  of  tin. 

Vignon  has  proposed  using  the  specific  gravity  of  the  silk 
sample  as  a  means  of  determining  the  proportion  of  weighting 
materials  present;  but  this  method  cannot  be  recommended  as 
being  at  all  practical,  as  the  specific  gravity  of  the  weighting 
materials  themselves  would  have  to  be  known.  The  specific 
gravity  of  the  silk  may  readily  be  determined  as  follows:  A 
small  sample  is  weighed  as  usual  in  the  air;  it  is  then  suspended 
in  benzene  and  the  weight  again  taken.  The  difference  between 
the  two  weighings  will  give  the  loss  of  weight  in  benzene;  this 
loss  divided  into  the  original  weight  in  air  and  multiplied  by 
the  density  of  the  benzene  will  give  the  specific  gravity  of  the 
silk.  The  specific  gravity  of  silk  and  of  other  fibres  deter- 
mined in  this  way  is  as  follows: 

Silk,  raw i .  30  to  i .  37 

Silk,  boiled-off i .  25 

Wool i .  28  to  i .  33 

Cotton i .  50  to  i .  55 

Mohair 1.3- 

Hemp i .  48 

Ramie 1.51  to  1.52 

Linen i .  50 

Jute i .  48 

For  the  examination  of  white  silk  Allen  recommends  the 
following:*  (i)  The  total  soluble  weighting  materials  are  deter- 
mined by  treating  a  known  weight  of  the  sample  four  to  five 
times  with  hot  water,  redrying,  and  weighing.!  As  the  hygro- 
scopic character  of  silk  is  very  variable,  it  is  best  to  employ  a 
blank  sample'  of  a  standard  silk,  and  after  redrying  until  the 
blank  sample  has  regained  its  normal  weight  the  test  sample 
is  weighed,  the  loss  representing  the  matters  soluble  in  water. 

*  Commer.  Org.  Anal.,  vol.  4,  p.  527. 

f  The  Milan  Commission  fixed  a  limit  of  1.5  per  cent  for  the  proportion  of 
soluble  materials,  and  gave  the  method  for  their  determination  as  follows:  The 
dried  silk  is  heated  for  thirty  minutes  with  ten  times  its  weight  of  distilled  water 
at  5°°-55°  C.  in  a  closed  metal  tube;  the  water  being  then  changed  and  the 
heating  continued  for  another  thirty  minutes,  at  the  same  temperature. 


556  THE  TEXTILE  FIBRES 

In  the  solution,  after  suitable  evaporation,  glucose  may  be 
determined  directly  by  means  of  Fehling's  solution  (see  p. 
552),  and  cane-sugar  after  inversion  by  boiling  with  dilute 
hydrochloric  acid.  Sulphates  and  chlorides  and  magnesium  may 
be  detected  and  determined  as  usual. 

Sulphates  are  detected  by  a  small  portion  of  the  solution 
in  a  test-tube,  adding  a  few  drops  of  dilute  hydrochloric  acid 
and  then  a  few  drops  of  a  solution  of  barium  chloride;  the 
production  of  a  white  precipitate  indicates  the  presence  of 
sulphates.  Chlorides  are  detected  by  adding  a  drop  of  nitric 
acid  to  a  test  portion  of  the  solution,  and  then  a  few  drops  of  a 
solution  of  silver  nitrate;  a  white  precipitate  will  indicate 
the  presence  of  .chlorides.  Magnesium  is  detected  by  adding 
to  the  test  portion  of  the  solution  a  few  drops  of  ammonia 
followed  by  a  solution  of  sodium  phosphate;  the  formation 
of  a  white  precipitate  indicates  the  presence  of  magnesium. 
These  tests  may  be  made  quantitative  by  taking  definite  aliquot 
portions  of  the  solution,  collecting  the  precipitates  produced, 
and  after  ignition  in  a  porcelain  crucible  weighing  as  barium 
sulphate.  BaSC>4,  silver  chloride,  AgCl,  and  magnesium  pyro- 
phosphate,  Mg2P2O7,  respectively. 

Stannic  oxide  (if  the  silk  has  been  weighted  with  tin  com- 
pounds) will  be  left  as  a  white  residue  on  igniting  a  sample  of 
the  silk  in  a  porcelain  crucible.  If  much  tin  is  present,  the  silk 
will  burn  with  difficulty,  and  the  ash  will  retain  the  shape  of 
the  original  silk.  The  weight  of  the  ash  (assuming  it  to  be 
wholly  stannic  oxide,  SnO2)  may  be  calculated  to  the  form  in 
which  the  tin  exists  in  the  weighted  silk  (as  metastannic  acid, 
Sn02.H20)  by  multiplying  it  by  the  factor  1.12.  . 

Silbermann,  Chem.  Zeit.,  vol.  20,  p,  472,  recommends  for 
the  analysis  of  white  silk  the  following  procedure:  A  weighed 
portion  of  the  silk  is  boiled  with  dilute  hydrochloric  acid 
to  dissolve  any  tannin  lakes  of  tin  or  other  metals,  and  in 
the  solution  tannin  is  tested  for  by  the  addition  of  an 
excess  of  sodium  acetate  and  ferric  chloride.  If  tannin  lakes 
are  present,  the  determination  of  the  weighting  materials 
consists  in:  (i)  precipitation  of  the  tannin  from  the  aqueous 


ANALYSIS  OF  TEXTILE   FABRICS  AND  YARNS         557 

solution  with  gelatin;  (2)  estimation  of  the  tannin  in  this 
precipitate,  and  of  sugar,  etc.,  in  the  filtrate;  (3)  succes- 
sive treatment  of  the  silk  with  dilute  hydrochloric  acid  and 
sodium  carbonate,  and  precipitation  of  tannin  from  both  solu- 
tions by  means  of  gelatin;  (4)  ignition  of  the  silk  and  deter- 
mination of  metallic  weighting.  If  the  ash  is  not  completely 
soluble  in  hot  moderately  concentrated  hydrochloric  acid,  it 
may  contain  barium  sulphate  or  silica.  To  calculate  the  per- 
centage of  weighting  material,  W  in  the  silk  examined,  Silber- 
mann  employs  the  following  formula,  in  which  a  is  the  weight 
of  the  sample  before  treatment,  b  the  weight  after  extraction 
with  water,  p  the  stannic  oxide  left  on  ignition,  and  d  the  loss 
in  weight  during  the  boiling  of  the  fibre  itself.  This  is  taken 
at  20  to  25  for  boiled-off  silk,  5  to  9  for  souple  silk,  and  o  to  2 
for  ecru. 

T~     0(100  —  d) 

W  =  -±—        --  100. 


The  detection  of  tin  or  aluminium  compounds  in  the  weight- 
ing of  white  silk  may  be  carried  out  by  dyeing  a  sample  of  the 
silk  with  alizarin  in  the  presence  of  chalk,  then  rinsing  and  soap- 
ing. Unweighted  silk  will  retain  only  a  pink  color;  if  weighted 
with  tin,  the  color  will  be  orange,  and  if  weighted  with  aluminium, 
the  color  will  be  red. 

The  presence  of  tin  in  weighted  silk  may  be  determined 
by  igniting  a  sample  of  the  silk  in  a  porcelain  crucible  until 
it  is  well  charred,  then  mixing  with  a.  little  potassium  cyanide 
and  heating  the  mixture  on  charcoal  in  a  blowpipe  flame.  Tin 
compounds,  if  present,  will  be  reduced  to  the  metal  in  the 
form  of  minute  globules,  the  identity  of  which  may  be  sub- 
sequently ascertained  by  the  usual  tests  for  tin. 

Dark-colored  and  black  silks  may  contain  hydroxides  of 
tin.  iron,  and  chromium,  fatty  matters,  tannin,  Prussian  blue 
and  various  coloring  matters.  Treatment  of  logwood-dyed 
silk  with  hydrochloric  acid  (1.07  sp.  gr.)  at  50°  to  60°  C.  will 
give  a  red  color  in  the  absence  of  Prussian  blue,  or  leave  a  blue 
black  color  if  it  is  present.  If  Prussian  blue  is  suspected,  the 


558  THE  TEXTILE  FIBRES 

silk  should  be  treated  with  dilute  caustic  soda,  the  solution  then 
acidulated  with  hydrochloric  acid,  and  a  few  drops  of  a  solu- 
tion of  ferric  chloride  then  added;  a  blue  precipitate  will  be 
produced  if  Prussian  blue  was  originally  present.  The  metallic 
oxides  in  the  residue  left  on  igniting  a  sample  of  the  silk  are 
best  examined  by  fusing  the  ash  with  a  mixture  of  nitre  and 
sodium  carbonate  in  a  platinum  or  silver  crucible.  The  fusion 
is  treated  with  water,  when  the  tin  and  chromium  will  go  into 
solution  as  sodium  stannate  and  chromate  respectively,  and  the 
iron  will  remain  insoluble  as  ferric  oxide.  After  filtering  and 
acidulating  the  filtrate  with  hydrochloric  acid,  the  tin  may  be 
thrown  down  as  sulphide  by  treatment  with  hydrogen  sulphide, 
and  after  filtering  off  the  latter  the  chromium  is  precipitated 
by  addition  of  ammonia.*  For  the  detection  of  tannin  a  sample 
of  the  silk  should  be  boiled  in  water,  and  a  few  drops  of  a  solu- 
tion of  ferric  acetate  added,  when  a  blue-black  color  is  produced 
in  the  presence  of  tannin.  The  amount  of  tannin  may  be  deter- 
mined by  dissolving  it  from  the  silk  by  means  of  an  alkaline 
soap-bath,  and  finding  the  loss  of  weight  on  redrying.  To 
determine  the  total  proportion  of  weighting  materials,  a  definite 
quantity  of  the  silk  dried  at  110°  C.  should  be  boiled  for  an 
hour  in  a  2  per  cent  solution  of  caustic  soda,  and  then  in  dilute 
hydrochloric  acid  (250  cc.  of  commercial  acid  per  litre).  This 
treatment  is  repeated  four  times,  washing  the  sample  between 
each  bath.  The  silk  must  be  carefully  handled,  as  it  becomes 
quite  brittle;  after  drying  at  110°  C.  it  is  weighed;  the  loss  in 
weight  represents  the  total  weighting  materials.  As  a  certain 
loss  of  silk  occurs  in  this  treatment,  the  amount  of  weighting 
material  found  is  generally  somewhat  in  excess  of  the  truth. 
The  chief  source  of  error,  however,  is  in  the  uncertainty  of  the 

*  Scheurer  and  Silbermann  (Bull.  Soc.  Ind.  Mulhouse,  1906,  p.  357)  give  the 
following  method  for  detecting  traces  of  tin  in  weighted  silk  (or  other  mordanted 
fabrics):  The  sample  is  boiled  with  a  4  per  cent  solution  of  hydrochloric  acid, 
and  the  tin  precipitated  from  the  resulting  solution  by  means  of  pure  zinc.  The 
precipitated  tin  is  filtered  out,  dissolved  in  some  hydrochloric  acid,  the  solution 
made  alkaline  with  sodium  hydrate,  and  then  tested  with  a  solution  of  five  parts 
bismuth  nitrate  in  500  parts  of  dilute  nitric  acid  fi  :  4).  A  brown  coloration  is 
obtained  if  even  a  trace  of  tin  is  present. 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         559 

allowance  to  be  made  for  loss  in  the  weight  of  the  silk  by  boil- 
ing off.  For  boiled-off  silk  this  figure  (d)  is  taken  at  25  per 
cent;  for  souple  silk  at  8  per  cent;  for  ecru  at  o  per  cent;  and 
for  fancy  silks  at  10  per  cent.  Calling  p  the  original  weight 
of  the  sample,  and  D  the  weight  after  treatment,  the  percentage 
of  weighting,  W,  may  be  calculated  from  the  following  formula: 


In  cases  where  the  treated  silk  leaves  a  sensible  amount  (A)  of 
ash  on  ignition,  the  following  formula  must  be  used: 


as  the  weight  of  the  ash,  if  multiplied  by  the  factor  1.25,  will 
give  approximately  the  amount  of  metallic  hydroxides  retained 
by  the  treated  silk. 

The  foregoing  method  of  Silbermann,  however,  is  not  suf- 
ficiently accurate  for  such  a  long  and  tedious  process. 

According  to  Ristenpart*  the  weighting  on  silk  may  be 
determined  by  extracting  1-3  gins,  of  the  sample  with  25 
cc.  of  a  4  per  cent  solution  of  caustic  soda.  He  considers 
this  more  expeditous  than  the  nitrogen  method,  while  it  is 
sufficiently  accurate  for  all  practical  purposes.  It  will  not 
answer,  however,  for  iron  mordanted  silk,  in  which  case,  it  is 
recommended  to  extract  the  organic  matter,  and  subsequently 
estimate  the  ash. 

The  method  of  analyzing  weighted  silk,  recommended 
by  Konigs  of  the  silk-conditioning  establishment  at  Crefeld, 
is  as  follows:  (i)  Determine  moisture  by  drying  at  110°  C. 
(2)  Fatty  matters  by  extraction  with  ether.  (3)  Boil  out  the 
silk-  glue  with  water.  (4)  Dissolve  out  Prussian  blue  with 
dilute  caustic  soda;  reprecipitate  by  acidifying  and  adding 
ferric  chloride,  ignite  precipitate  with  nitric  acid,  and  weigh 
as  ferric  oxide;  i  part  of  Fe2Os  =  i.5  parts  of  Prussian  blue. 

*  FSrb.  Zeit.,  1909,  126. 


560  THE  TEXTILE  FIBRES 

(5)  Estimate  stannic  oxide  in  ash  of  siik  and  calculate  as  catechu- 
tannate  of  tin;  i  part  of  SnO2  =  3-33  parts  of  catechu-tannate. 

(6)  Estimate  total  ferric  oxide  in  ash,  subtract  that  existing 
as    Prussian    blue,    and    the    amount    naturally    present    in 
dyed  silk  (0.4  to  0.7  per   cent),  and   calculate   the   remainder 
to    tannate   of   iron;     i    part   of    Fe2O3  =  7.2    parts    of    ferric 
tannate. 

For  the  extraction  of  weighting  materials  from  black-dyed 
silk  Heermann  *  recommends  the  use  of  a  mixture  of  equal  parts 
of  glycerin  and  normal  potassium  hydroxide  solution.  The 
sample  of  silk  is  heated  with  this  reagent  to  about  80°  C.  on 
the  water-bath  for  ten  minutes.  Black  dyes  and  Prussian 
blue  are  rapidly  extracted  by  this  reagent  without  injury  to 
the  silk  fibre.  In  case  the  weighting  materials  contain  tin 
compounds  in  addition  to  Prussian  blue,  successive  extrac- 
tions should  be  given  with  the  glycerin-alkali  solution,  with 
cold  20  per  cent  hydrochloric  acid,  and  again  with  glycerin- 
alkali. 

Perhaps  the  most  accurate  method  of  analyzing  silk  for 
total  amount  of  weighting  is  to  determine  the  amount  of  nitro- 
gen present  as  silk  by  Kjeldahl's  process. f  To  do  this  it  is 
first  necessary  to  remove  all  gelatin,  Prussian  blue,  or  other 
nitrogenous  matters.  This  is  effected  by  boiling  a  weighed 
quantity  of  the  silk  (about  2  gms.)with  a  2  per  cent  solution 
of  sodium  carbonate  for  thirty  minutes.  The  silk  is  then  washed, 
and  heated  to  60°  C.  for  thirty  minutes  in  water  containing 
i  per  cent  of  hydrochloric  acid,  and  afterward  well  washed 
in  hot  water.  This  treatment  with  alkali  and  acid  should  be 
repeated  until  the  sample  no  longer  has  a  blue  color.  With 
souple  or  ecru  silks,  ammonia  or  ammonium  carbonate  should 
be  used  instead  of  sodium  carbonate,  and  the  silk  should  be 
finally  boiled  for  an  hour  and  a  half  in  a  solution  containing 
25  gms.  of  soap  per  litre.  After  this  preparation  the  nitrogen 
determination  is  conducted  as  follows:  The  sample  is  placed 


*  Farber.  Zeti.,  1909,  p.  75. 

t  Gnehm  and  Blenner,  Rev.  Gen.  Mat.  Col.,  April,  1898. 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         561 

in  a  round-bottomed  flask  of  hard  glass,  and  treated  with  about 
20  cc.  of  strong  sulphuric  acid,  with  the  addition  of  a  single 
drop  of  mercury.  The  flask  is  then  heated,  gently  at  first, 
and  then  to  a  vigorous  boil;  then  10  gms.  of  potassium  sulphate 
are  added  and  the  boiling  continued  until  the  contents  of  the 
flask  are  clear  and  colorless.  The  contents  are  then  washed 
into  a  distill  ing-flask  and  connected  with  a  suitable  condenser. 
By  means  of  a  tap-funnel,  an  excess  of  caustic  soda  solution  is 
gradually  added,  together  with  a  little  sodium  sulphide  to  decom- 
pose any  nitrogen  compounds  of  mercury  that  may  have  been 
formed.  Some  granulated  zinc  is  placed  in  the  flask  to  pre- 
vent bumping,  and  the  distillate  is  collected  in  a  measured 
quantity  of  standard  acid,  which  takes  up  the  ammonia  that 
distils  over.  Excess  of  acid  is  determined  by  titration  with 
standard  alkali,  using  methyl  orange  as  an  indicator  of  neutrality. 
The  above  method  is  based  on  the  fact  that  when  silk  (in  com- 
mon with  the  great  majority  of  other  nitrogenous  organic 
substances)  is  heated  with  concentrated  sulphuric  acid,  the 
whole  of  the  nitrogen  present  is  eventually  converted  into 
ammonia.  Air-dried  silk  with  n  per  cent  of  hygroscopic 
moisture  contains  17.6  per  cent  of  nitrogen,  consequently  the 
amount  of  true  silk  in  a  sample  may  be  obtained  by  multiplying 
the  percentage  of  nitrogen  found  by  the  factor  5.68.  This 
method  yields  very  accurate  results  if  the  determination  of  the 
nitrogen  is  carefully  conducted. 

Sisley  *  recommends  that  the  Kjeldahl  method  be  carried 
out  as  follows:  About  2  gms.  of  the  silk  are  boiled  for  ten 
minutes  with  a  25  per  cent  acetic  acid  solution,  then  rinsed  in 
water,  immersed  for  ten  minutes  in  a  3  per  cent  solution  of 
trisodium  phosphate  at  50°  C.,  rinsed  again,  and  then  boiled 
twice  for  twenty  minutes  in  a  solution  containing  3  per  cent 
of  soap  and  0.2  per  cent  of  sodium  carbonate.  The  silk  thus 
purified  is  wrapped  in  a  piece  of  cotton  cloth  and  gently  heated 
with  20  cc.  of  strong  sulphuric  acid,  10  gms.  of  potassium 
sulphate,  and  0.5  gm.  of  copper  sulphate  until  effervescence 

*  Reo.  Gen.  Mat.  Col.,  1907,  p.  97. 


562  THE  TEXTILE  FIBRES 

ceases,  after  which  the  liquid  is  boiled  until  colorless,  and  the 
ammonia  distilled  in  the  usual  manner. 

Moyret  recommends  the  following  method  for  the  analysis 
of  weighted  silks: 

(a)  Moisture. — This  is  best  determined  in  a  proper   con- 
ditioning oven,  but  if  this  is  not  available  it  is  sufficient  to  dry 
10  gms.  of  the  silk  in  an  oven  at  110°  C.  for  one  hour,  or  until 
constant  weight  is  obtained.     If  the  loss  exceeds  15  per  cent 
it  may  be  assumed  that  the  silk  has  been  weighted  with  hygro- 
scopic substances. 

(b)  Soluble  Matters. — The  dried  sample  is  boiled  in  distilled 
water,  mixed,  dried,  and  weighed.     Such  substances  as  glycerin, 
sugar,    magnesium    sulphate,    potassium    sulphate,    etc.,    will 
pass  into  solution,  and  the  loss  in  weight  will  represent  soluble 
matters. 

(c)  Extract  with  Petroleum  Ether. — The  sample  is  extracted 
for  twenty  minutes  with  petroleum,  dried,  and  weighed.     Loss 
in  weight  represents  extractive  matters.     The  extract  may  be 
evaporated  and  examined. 

(d)  Action  of  Hydrochloric  Acid. — The  sample  is  treated  for 
fifteen  minutes  at  100°  F.,  with  dilute  (1:2)  hydrochloric  acid. 
If  ferric  tannate  has  been  used  for  weighting,  the  silk  will  become 
decolorized  and  the  acid  liquid  will  have  a  dirty  brown  color 
which  does  not  turn  violet  on  the  addition  of  lime-water.    Should 
the  reddish  solution  turn  violet  with  this  latter  reagent,  log- 
wood   is   indicated;    while   if   the   fibre   becomes    dark   green 
and   the  liquid   yellow  and  unchanged  by  lime-water,   Berlin 
blue  is  present.     If  the  fibre  is  green  and  the  liquid  red,  changing 
to   violet   with   addition   of   lime-water,   it   indicates   logwood 
black  dyed  on  a  ground  of  Berlin  blue.     Iron,   chrome,   and 
alumina  mordants  must  be  tested  for  in  the  solution. 

(e)  Action  of  Alkalies. — The  silk  is  next  boiled  in  a  dilute 
solution  of  soda  ash,  which  will  dissolve  the  tannin  from  the 
fibre.     The  tannin  may  be  detected  by  addition  of  iron  salts 
to  the  alkaline  solution. 

(/)  Estimation  of  Ash. — A  weighed  sample  of  the  silk  is 
ignited  in  a  crucible   (platinum  preferred).     If  the  weight  is 


ANALYSIS  OF  TEXTILE  FABRICS   AND  YARNS         563 

more  than  i  per  cent  it  indicates  that  the  silk  has  been  weighted, 
and  the  ash  should  be  further  examined. 

A  method  for  the  determination  of  the  weighting  on  silk 
which  appears  to  be  capable  of  yielding  very  good  results  is 
that  suggested  by  Gnehm.*  It  depends  on  the  fact  that,  the 
silk  fibre  does  not  appear  to  be  injured  by  treatment  with  either 
hydrofluosilicic  acid  or  hydrofluoric  acid.  The  method  is 
carried  out  as  follows:  About  2  gms.  of  the  silk  to  be  tested 
are  immersed,  with  frequent  stirring,  for  one  hour  at  the  ordinary 
temperature  of  100  cc.  of  a  5  per  cent  solution  of  hydrofluosilicic 
acid.  The  treatment  is  then  repeated  with  100  cc.  of  fresh 
acid  of  the  same  strength.  The  silk  is  then  washed  several 
times  with  distilled  water  and  dried.  The  loss  in  weight  cor- 
responds to  the  amount  of  inorganic  weighting  materials 
present.  This  method  serves  very  well  with  silk  weighted 
with  stannic  phosphate  and  silicate,  but  does  not  appear 
to  be  suitable  for  the  estimation  of  weighting  on  black- 
dyed  silks  containing  iron  salts.  It  is  said  that  oxalic  acid 
may  also  be  used,|  for  the  purpose  of  removing  the  inorganic 
weighting  materials  from  silks,  without  injury  to  the  silk  fibre 
itself. 

Gnehm  and  Diirsteler  J  give  the  following  rapid  extraction 
methods  for  the  analysis  of  weighted  silks: 

(a)  For  While  or  Colored  Silks. — The  sample  is  twice 
extracted  for  fifteen  minutes  with  hydrofluoric  acid  of  i  to  2 
per  cent  strength  at  5o°-6o°  C.  In  the  case  of  silk  weighted 
with  tin  silicate  and  phosphate  the  material  may  be  treated 
with  dilute  hydrochloric  acid  and  hydrogen  sulphide  at  7o°-8o° 
C.  for  thirty  minutes,  then  for  five  minutes  with  a  4  per  cent 
solution  of  sodium  sulphide  at  4o°-56°  C..  and  lastly  for  fifteen 
minutes  with  a  2  per  cent  solution  of  sodium  carbonate  at  6o°-7o° 
C.  The  residue  after  this  treatment  may  be  weighed  as  pure 
silk  fibroin.  If  aluminium  compounds  are  present  in  the 
weighting  these  extractions  must  be  repeated. 

*  Zeits.  Farben-u.  Text.  Chem.,  1903,  p.  209. 

t  Miiller,  Zeits.  Farben-u.  Text.  Chem.,  1903,  p.  160. 

iFarber.  ZeiL,  1906,  p.  218. 


564  THE  TEXTILE  FIBRES 

(b)  For  Black  Silks. — If  the  weighting  material  is  tin  phos- 
phate alone,  extract  with  hydrofluoric  acid  (1-2  per  cent  solu- 
tion), and  follow  by  a  treatment  with  a  2  per  cent  solution  of 
sodium  carbonate.  In  the  presence  of  iron  compounds  it  is 
best  to  extract  the  silk  with  a  i  per  cent  solution  of  hydrochloric 
acid,  then  with  a  4  per  cent  solution  of  sodium  sulphide,  and 
finally  with  a  2  per  cent  solution  of  sodium  carbonate. 

Taking  all  things  into  consideration,  the  author  considers 
the  following  method  to  be  the  one  best  adapted  for  the  com- 
mercial analysis  of  tin-weighted  silks:  A  portion  (about  0.5  gm.) 
of  the  sample  is  placed  in  a  weighing-bottle  and  dried  in 
an  air-bath  at  105°  C.  to  constant  weight.  It  is  then  boiled 
in  a  2  per  cent  solution  of  hydrofluoric  acid  for  five  minutes, 
rinsed  with  water,  and  boiled  for  five  minutes  in  a  2  per  cent 
solution  of  soda  ash  and  washed.  This  alternate  treatment 
with  the  hydrofluoric  acid  and  soda  ash  solutions  is  repeated 
three  times,  after  which  the  sample  is  finally  rinsed,  dried  at 
105°  C.,  and  reweighed.  The  loss  in  weight  will  represent 
weighting  materials.  The  hydrofluoric  acid  may  be  prepared 
by  diluting  n  cc.  of  commercial  hydrofluoric  acid  to  400  cc. 
with  water,  and  the  soda  ash  solution  by  dissolving  2  gms. 
of  sodium  carbonate  in  100  cc.  of  water.  Three  alternate 
treatments  with  these  reagents  will  generally  suffice  to  remove 
all  weighting  materials  without  appreciable  injury  to  the  silk 
fibre,  though  to  be  accurate  the  treatments  should  be  repeated 
until  no  further  loss  in  weight  is  observed.* 

The  amount  of  weighting  on  silk  is  usually  calculated  on  a 
basis  of  ounces  per  pound  of  raw  silk,  and  expressed  between 
a  limiting  variation  of  2  ozs.;  and  it  is  further  reckoned  that 
i  pound  of  raw  silk  is  equivalent  to  12.4  ozs.  of  pure  silk  fibre 
(boiled-off) .  A  sample  of  silk  described  as  22/24,  f°r  example, 
would  mean  that  22  to  24  ozs.  of  such  silk  would  be  equivalent 

*  This  method  gives  good  results  if  the  weighting  consists  of  tin-phosphate- 
silicate.  For  black  silks  heavily  weighted  with  iron  salts,  and  especially  if  Prussian 
blue  is  present  in  any  considerable  amount,  the  results  will  be  low,  and  it  is 
recommended  to  employ  the  Kjeldahl  nitrogen  method  as  described  in  the  fore- 
going pages. 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         565 


to  1 6  ozs.  of  raw  silk.  The  amount  of  weighting  as  determined 
by  the  chemist  should  be  calculated  to  percentage  on  the  actual 
silk  present,  and  then  by  use  of  the  following  table  the  cor- 
responding ounces  may  be  found: 


Per  Cent 
Weighting. 

Ounces. 

Per  Cent. 
Weighting. 

Ounces. 

o-  13 

12/14 

142-158 

30/32 

13-    29 

14/16 

158-174 

32/34 

29-  45 

16/18 

174-190 

34/36 

45-  61 

18/20 

190-206 

36/38 

61-  77 

20/22 

2O6-222 

38/40 

77-  93 

22/24 

222-238 

40/42 

93-109 

24/26 

238-254 

42/44 

109-125 

26/28 

154-270 

44/46 

125-142 

28/30 

270 

46/48 

For  example:  A  sample  of  silk  dried  at  105°  C.  to  constant 
weight  proved  to  be  0.45  gm.  After  treatments  with  hydro- 
fluoric acid  and  soda  ash  solutions  as  above  described,  dried 
again  at  105°  C.,  and  reweighed,  gave  0.31  gm.  of  silk  as  a 
residue.  Hence, 


o.45  gram  =  weigh  ted  silk; 
0.31      "    =pure  silk; 


0.14 


and 


0.14X100 
0.31 


weigh  ting, 


=  45  per  cent  weighting, 


calculated  from  a  basis  of  pure  silk.  By  reference  to  the  fore- 
going table,  it  is  seen  that  45  per  cent  weighting  corresponds 
to  18/20  ozs.  of  silk. 

As  the  silk  fibre  is  very  uniform  in  its  structure  and  weight 
for  any  given  length,  an  empirical  method  for  determining  the 
weighting  on  silk  is  as  follows:  The  size  of  a  single  cocoon- 


566  THE  TEXTILE   FIBRES 

thread  averages  2  J  denier  (see  p.  114);  that  is  to  say,  500 
metres  of  such  a  filament  will  average  0.125  gm-  in  weight. 
Hence,  if  yarn  is  being  tested,  a  sample  is  observed  under  the 
microscope  and  the  number  of  individual  filaments  present  is 
counted.  A  convenient  length.  of  the  yarn  is  then  taken  and 
weighed,  and  from  this  the  weight  of  500  metres  is  calculated. 
By  multiplying  the  number  of  filaments  observed  by  the  factor 
0.125,  we  obtain  the  weight  of  500  metres  of  the  yarn  as  pure 
silk.  The  difference  between  this  weight  and  the  former 
represents  weighting,  from  which  the  percentage  and  ounces 
of  weighting  may  be  calculated  as  given  in  the  foregoing  para- 
graph. 

For  example:  A  portion  of  a  single  thread  from  a  skein 
of  silk  yarn  was  carefully  teased  out  so  as  to  separate  the  individ- 
ual filaments,  and  these  were  counted  under  a  microscope. 
A  series  of  three  observations  gave  19,  17,  and  20  filaments, 
or  a  mean  of  18.6.  The  weight  of  50  metres  of  the  silk  was 
0.2623  gm.  Hence 

0.2623X10  =2.623  grams  =  weight  of  500  metres; 
0.125X18.6  =  2.325  =  weight  of  500  metres  of  pure  silk; 

0.298  =  weigh  ting, 

and 

°-298Xl0°  =12.8  per  cent  weighting, 


and  this  is  equivalent  to  12/14  oz.  silk. 

In  case  the  sample  to  be  examined  is  a  woven  fabric,  it  will 
be  necessary  to  pick  apart  the  warp-  and  weft-  threads,  and  make 
separate  counts  of  the  filaments  in  each;  then  definite  lengths 
of  these  threads  may  be  measured  off  and  weighed,  and  the  cal- 
culation conducted  as  before.  In  making  the  count  of  the 
filaments  in  each  thread  of  silk,  the  latter  should  be  teased  out  as 
carefully  as  possible,  in  order  to  separate  the  individual  filaments. 
This  may  readily  be  done  by  laying  the  thread  on  a  glass  micro- 
scope slide  slightly  moistened  with  water  and  separating  the 
filaments  with  a  needle.  The  number  of  filaments  mav  then 


ANALYSIS  OF  TEXTILE   FABRICS  AND  YARNS         567 

be  counted  through  the  microscope,  using  a  low  magnifica- 
tion. The  count  may  also  be  made  with  the  aid  of  a  good  magni- 
fying-glass,  but  with  more  difficulty  and  less  accuracy  than 
when  a  microscope  is  employed.  At  least  three  separate 
counts  of  different  threads  should  be  made,  and  the  average  of 
these  taken  as  the  true  number. 

In  case  the  length  of  the  silk  threads  is  measured  in  yards 
and  not  metres,  a  convenient  amount  to  take  for  a  test  is  20 
yds.,  then  the  following  formula  will  hold: 

Let 

A  =  weight  of  500  metres  of  the  weighted  silk=weight  of  20 

yds.  X  27.3; 
B  =  weight  of  500  metres  of  pure  silk  =  number  of  filaments 

Xo.i25, 
and 

A-B 


B 


X 1 00  =  per  cent  of  weighting. 


The  above  formula  is  for  weights  expressed  in  grams;   in 
case  the  weights  employed  are  grains,  we  have 

A  =  weight  of  20  yds.  X  2  7 .3 ; 
B  =  number  of  filamentsXi.9i2, 


and 

A-B 


X 1 00  =  per  cent  of  weighting. 


B 
These  formulas  may  be  simplified  as  follows: 

(a)  In  case  gram  weights  are  used 

w  =  weight  of  20  yds.  of  the  silk; 
n  =  number  of  filaments ; 

2i&w— n.  .  c      .  ,  .. 

X 100  =  per  cent  of  weighting. 

n 

(b)  In  case  grain  weights  are  used 

I4..2W  —  n  ,     . 

-  X 1 00  =  per  cent  of  weighting. 
n 


568  THE  TEXTILE  FIBRES 

The  accuracy  of  this  method  for  determining  the  degree  of 
weighting  of  silk  is  based  on  the  theory  that  the  fibre  is  very 
uniform  in  size,  and  hence  the  weight  of  a  given  length  of  fibre 
may  be  assumed  as  being  constant.  This,  however,  is  only 
true  within  certain  limits  and  with  respect  to  certain  grades 
of  silk.  By  reference  to  the  table  on  page  114  it  will  be  seen 
that  the  variation  in  size  (or  weight  for  a  given  length)  of  silks 
from  different  countries  is  quite  considerable;  hence,  to  apply 
the  foregoing  method  properly,  the  origin  of  the  silk  should 
be  known.  In  the  case  of  tussah  or  other  varieties  of  wild 
silk  the  variation  in  size  is  much  more  considerable;  hence  the 
limit  of  error  in  this  method  is  much  larger  and  the  results  are 
not  sufficiently  accurate  to  be  at  all  reliable. 

8.  Oil  and  Grease  in  Yarns  and  Fabrics. — An  estimation  of 
the  amount  of  oil  and  grease  is  frequently  required  for  woolen 
or  worsted  cloth,  yarn,  tops,  roving,  etc.  A  method  leading 
to  approximate  results,  which  are  generally  sufficiently  accurate 
for  commercial  purposes,  is  to  weigh  off  a  sample  of  the  material 
to  be  tested  and  scour  it  for  thirty  minutes  in  a  solution  con- 
taining 5  gms.  of  good  quality  soap  per  litre  at  a  temperature 
of  140°  F.  It  is  then  rinsed  well  in  warm  water  a  couple 
of.  times  to  remove  all  of  the  soapy  liquor,  and  then  dried. 
Before  reweighing  it  should  be  left  in  the  air  for  about 
an  hour,  so  as  to  come  to  the  same  hygroscopic  condition 
as  when  first  weighed.  The  loss  in  weight  will  represent  the 
oil,  grease,  and  any  dirt  in  the  fibre,  and  may  be  called  the 
"  scouring  loss." 

A  more  accurate  method  to  determine  the  oil  and  grease 
is  to  weigh  off  about  5  gms.  of  the  material  and  agitate  in  a 
flask  with  about  100  cc.  of  petroleum  ether  for  twenty  minutes. 
This  will  dissolve  all  oily  matters  present,  and  the  liquid  may  be 
poured  into  a  weighed  evaporating-dish.  The  residual  fibre 
is  washed  with  about  100  cc.  more  of  petroleum  ether;  the 
latter  is  added  to  the  first  extraction  and  the  whole  evaporated 
to  dryness  on  a  water-bath,  and  the  weight  of  the  residue  of 
oil  in  the  evaporating-dish  is  determined,  or  the  extracted 
fibre  may  be  removed  from  the  flask,  dried,  exposed  to  the  air 


ANALYSIS   OF  TEXTILE  FABRICS  AND  YARNS         569 

for  an  hour  and  reweighed,  and  the  loss  in  weight  will  represent 
grease  and  oil. 

In  the  two  preceding  methods  where  the  air-dry  weights  are 
used,  care  should  be  especially  taken  to  weigh  the  material 
before  and  after  under  the  same  hygroscopic  conditions,  other- 
wise considerable  variations  in  results  may  be  obtained  by 
reason  of  the  fibre  absorbing  a  greater  or  less  quantity  of  mois- 
ture; where  accurate  results  are  demanded,  it  will  be  neces- 
sary to  make  three  weighings,  as  follows:  (a)  the  weight  of 
the  air-dry  material,  (b)  the  weight  of  the  material  after  drying 
at  105°  C.  for  one  hour,  (c)  the  weight  of  the  extracted  material 
after  drying  for  one  hour  at  105°  C.  In  this  manner  the  some- 
what uncertain  factor  of  moisture  is  eliminated.  The  percentage 
of  grease  in  the  material,  however,  should  be  calculated  on  the 
weight  of  the  air-dry  fibre.  For  example:  a  sample  of  woolen 
yarn  weighing  5.026  gms.  was  dried  at  105°  C.  for  one  hour 
and  when  weighed  again  gave  4.516  gms.;  after  extraction 
with  petroleum  ether  and  drying  again  as  before,  it  weighed 
4.271  gms.  The  amount  of  grease  in  this  case  was  therefore 
4.516  —  4.271=0.245  gms.  or  (0.245X100)^5.026=4.67  percent. 

A  still  better  and  more  accurate  method  for  the  determina- 
tion of  grease  is  to  treat  a  weighed  sample  of  the  material  in  a 
Soxhlet  extraction  apparatus  with  petroleum  ether,  evaporating 
off  the  solvent  and  weighing  the  residue  of  grease.  The  analysis 
is  determined  as  follows:  The  small  flask  of  the  apparatus 
is  weighed  and  then  about  half -filled  with  petroleum  ether  (about 
50  to  75  cc.);  about  2  gms.  of  the  material  to  be  extracted  is 
accurately  weighed  and  placed  in  the  extraction  tube  or  capsule, 
after  which  the  several  parts  of  the  apparatus  are  connected 
and  the  flask  is  heated  on  a  water-bath  until  all  the  oil  or  grease 
has  been  extracted  and  dissolved  by  the  petroleum  ether. 
According  to  the  form  of  apparatus  employed,  this  may  require 
from  twenty  minutes  to  one  hour.  The  flask  is  then  removed 
and  the  solvent  is  distilled  off.  The  residual  grease  in  the  flask 
is  then  dried  for  one-half  hour  on  the  water-bath  and  after 
cooling  weighed.  The  increase  in  the  weight  of  the  flask 
represents  the  amount  of  grease. 


570 


THE  TEXTILE   FIBRES 


9.  Estimation  of  Finishing  Materials  on  Fabrics. — Cotton 
fabrics  are  quite  generally  sized  or  otherwise  finished  for  the 
purpose  of  giving  the  cloth  a  better  handle  or  a  greater  weight. 
For  this  purpose  a  wide  variety  of  substances  may  be  used,  but 
starch  is  nearly  always  the  basis  of  the  sizing.  Soaps,  fats, 
gelatin,  vegetable  mucilages,  resin,  and  china  clay  are  also  of 
common  occurrence.  In  some  cases  hygroscopic  salts,  such  as 
calcium  chloride,  magnesium  chloride,  or  zinc  chloride  are  used 
to  obtain  certain  effects  or  to  increase  the  weight  of  the  goods.* 
Woolen  goods  are  sometimes  sized  or  weighted  in  a  similar 
manner,  both  for  purposes  of  producing  certain  finishes  and  of 
fraudulently  increasing  the  weight  of  the  fabric. 

According  to  Hoyer,f  cotton  cloth  in  the  gray  or  unbleached 
state  should  consist  approximately  of  83  per  cent  fibre  7  per 
cent  moisture,  8.5  per  cent  of  starch  and  fatty  matters  (used 
for  softening  the  yarn  and  sizing  the  warp),  and  1.5  per  cent  of 
ash.  After  boiling-out  and  bleaching,  however,  only  78  per 
cent  of  fibre  is  left,  so  that  by  the  addition  of  dressing  the 
finished  cloth  consists  of  78  per  cent  fibre,  7  per  cent  moisture, 
7  per  cent  starch,  and  7.5  per  cent  mineral  matter.  If  the 
amount  of  fibre  falls  below  78  per  cent  in  bleached  calico  or 
much  below  83  per  cent  in  gray  calico,  it  may  be  supposed  that 
the  cloth  is  loaded. 

*  Thompson,  Sizing  of  Cotton  Goods,  p.  150,  gives  the  following  typical  analyses 
of  cotton  fabrics: 


I. 

II. 

III. 

IV. 

V. 

VI. 

Material  : 

Per  Cent. 

Per  Cent. 

Per  Cent. 

Per  Cent. 

Per  Cent. 

Per  Cent. 

Fibre  

47.29 

53  -02 

60.75 

70.84 

80.51 

81.78 

Normal  moisture  .... 

4.11 

4.61 

5-28 

6.16 

7.02 

7.11 

Weight  of  cloth  

5I-40 

57-63 

66.03 

77.00 

87-53 

88.89 

Dressing: 

Water  

6.01 

5.02 

4-65 

3-07 

2.OI 

2.89 

Dressing  and  fat.  ... 

12.77 

13-36 

13-33 

12.43 

8.30 

3  •  33 

Mineral  matter  

29.82 

23-99 

15-99 

7-50 

2.16 

4.89 

Weight  of  dressing.  .  . 

48.60 

42.37 

33-97 

23.00 

12.^7 

ii.  ii 

f  Dammer's  Lexikon  der  Verfalschungen. 


ANALYSIS  OF  TEXTILE    FABRICS  AND   YARNS         571 

Linen  fabrics  should  contain  but  a  small  amount  of  finishing 
or  dressing  materials.  Usually  a  small  quantity  of  starch  is 
required  for  the  purpose  of  sizing  the 'warps,  but  no  mineral 
matter  should  be  present  beyond  that  to  be  found  in  the  natural 
fibre  itself.  Linen  cloth  should  not  lose  more  than  5  per  cent 
when  boiled  in  water. 

Woolen  goods  are  often  finished  with  Irish  moss,  glue, 
gelatin,  dextrin,  starch,  albumen,  sodium  silicate,  etc. 

In  the  finishing  of  silk  fabrics  gelatin,  tragacanth,  gum 
arabic,  shellac,  etc.,  are  used. 

The  following  is  a  brief  and  general  survey  of  the  determina- 
tion of  finishing  materials  on  textile  fabrics: 

(a)  Moisture  is  determined  in  the  usual  manner  as  described 
above.     If  the  amount  of  moisture  is  large  a  high  degree  of 
weighting  or  finish  may  be  suspected,  especially  in  the  case  of 
cotton  goods,  since  starch  absorbs  much  more  water  than  the 
pure  cotton  fibre. 

(b)  Benzol  Extract. — The   dried   sample  is  extracted  in   a 
Soxhlet  with  benzol.     This  will  dissolve  out  fats,  rosin,  wax, 
paraffin,  etc.     The  extract  is  distilled  and  the  amount  of  solid 
residue  determined. 

(c)  Water  Extract. — The  sample  is  then  boiled  in  water  for 
one  hour,  which  will  remove  dextrin,  starch,  glue,  gum  arabic, 
sugar,  Irish  moss,  tragacanth,  etc.,  as  well  as  various  insoluble 
matters  such  as  talc,  China  clay,  etc.  which  are  held  on  the 
fibre  by  the  various  finishes.     The  water  extract  is  filtered, 
and  the  solution  may  then  be  examined  for  the  various  ingre- 
dients.* 

(d)  Mineral  Matters. — These  may  be  determined  by  ignit- 
ing a  weighed  sample  of  the  fabric  to  a  complete  ash.     The 
ash  may  further  be  tested  in  order  to  determine  its  various 
ingredients,  f 

*  See  Massot,  Appretur-und  Schlichte-Analyse. 

f  Prior  gives  the  following  method  for  testing  the  ash  of  textile  fabrics:  A 
portion  of  the  ash  is  boiled  with  nitric  acid  and  a  strong  effervescence  will 
indicate  the  presence  of  metallic  carbonates.  The  solution  is  evaporated  to 
dryness  on  a  water-bath,  taken  up  with  nitric  acid  and  water,  any  insoluble  residue 


572  THE  TEXTILE  FIBRES 

10.  Testing  the  Waterproof  Quality  of  Fabrics. — A  large 
variety  of  fabrics  are  now  finished  so  as  to  be  more  or  less  water- 
proof, or,  more  strictly  speaking,  water-resistant.  Fabrics 
of  cotton,  wool,  silk,  or  of  mixed  fibres  may  be  given  this  property. 
It  is  not  the  purpose  at  this  point  to  enter  into  the  methods  by 
which  waterproofing  is  carried  out,  but  simply  to  give  the 
methods  employed  for  testing  such  fabrics. 

In  Germany  the  following  test  is  prescribed  for  sail-cloth: 
A  sample  of  the  cloth  10  inches  square  is  folded  like  a  filter- 
paper  and  placed  in  a  suitable  glass  funnel  where  300  cc.  of  wetter 
are  poured  upon  it  and  it  is  left  for  twenty-four  hours.  At  the 
end  of  this  time  only  a  few  equally  distributed  drops  of  water 

filtered  off,  and  the  filtrate  treated  with  hydrogen  sulphide.  A  black  precipitate 
will  indicate  the  presence  of  lead.  This  should  be  filtered  off,  dissolved  in  nitric 
acid,  and  tested  with  sulphuric  acid,  potassium  chromate  or  other  reagents  to 
confirm  the  presence  of  lead.  The  filtrate  is  tested  for  iron  by  neutralizing  with 
ammonia  and  adding  ammonium  sulphide.  The  filtrate  from  this  precipitate  is 
tested  for  barium,  calcium,  and  magnesium  by  acidulating  with  hydrochloric  acid, 
boiling  to  expel  the  liberated  hydrogen  sulphide,  then  neutralizing  with  ammonia 
and  adding  ammonium  chloride  and  carbonate.  Any  precipitate  is  filtered  off, 
washed,  and  dissolved  in  dilute  hydrochloric  acid  and  this  solution  is  tested  by 
the  addition  of  calcium  sulphate  solutions.  Immediate  precipitate  indicates  the 
presence  of  barium.  Another  portion  of  this  filtrate  is  tested  with  ammonium 
oxalate  solution  when  a  precipitate  will  indicate  the  presence  of  calcium.  The 
ash  which  is  insoluble  in  nitric  acid  may  contain  silica  resulting  from  the  decom- 
position of  magnesium  silicate  or  sodium  silicate  together  with  barium  sulphate,  tin 
oxide,  gypsum,  or  clay.  This  residue  is  boiled  with  sodium  carbonate  which  will 
dissolve  the  silicate  and  decompose  the  gypsum.  After  filtration,  the  precipitate 
is  washed,  dissolved  in  cold  dilute  hydrochloric  acid  and  tested  for  the  presence 
of  iron  and  calcium  as  above  indicated.  The  filtrate  is  acidulated  with  hydro- 
chloric acid,  evaporated  to  dryness,  and  the  residue  is  taken  up  with  water  and 
hydrochloric  acid.  Any  insoluble  residue  of  silica  is  separated  and  the  filtrate 
is  tested  for  sulphuric  acid  by  the  addition  of  barium  chloride.  The  residue 
which  is  undecomposed  by  sodium  carbonate  or  insoluble  in  hydrochloric  acid  may 
contain  barium  sulphate,  clay  or  tin  oxide.  This  is  fused  with  10  parts  of  sodium 
carbonate  in  a  porcelain  crucible  and  the  melted  mass  is  treated  with  water  and 
sodium  bicarbonate  and  filtered.  The  water  residue  is  next  boiled  with  strong 
hydrochloric  acid  and  the  liquid  treated  with  hydrogen  sulphide.  A  yellow 
precipitate  will  indicate  the  presence  of  tin.  This  is  filtered  off  and  half  the  filtrate 
is  tested  for  aluminium  by  the  addition  of  ammonia,  and  the  other  half  for  barium 
by  the  addition  of  sulphuric  acid.  The  filtrate  from  the  fusion  is  treated  with 
hydrochloric  acid  and  partially  evaporated  which  will  throw  out  the  silica.  The 
soluble  portion  is  tested  for  the  presence  of  sulphates  by  the  addition  of  barium 
chloride. 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         573 

should  be  discovered  on  the  under  surface  of  the  cloth,  and  the 
fabric  should  not  be  wet  through. 

Gawalowski  *  describes  an  apparatus  for  determining  the 
waterproof  qualities  of  a  fabric  as  follows:  The  sample  of  the 
cloth  is  attached  to  the  open  end  of  a  graduated  tube  (a  burette 
will  serve  the  purpose,  using  the  large  opening  for  the  cloth), 
which  is  then  filled  with  a  column  of  water  12  inches  in  height. 
At  the  end  of  twenty-four  hours  an  observation  is  made  as  to 
how  much  water  has  passed  through  the  cloth. 

n.  Testing  the  Liability  of  Waterproofed  Fabrics  to  Spon- 
taneous Combustion. — In  the  waterproofing  of  fabrics  the  mate- 
rials employed  to  render  the  goods  waterproof  may  often 
introduce  the  risk  of  their  becoming  spontaneously  inflammable. 
Oils  that  readily  absorb  oxygen  if  used  in  large  amount  upon 
a  fabric  may  readily  cause  the  development  of  sufficient  heat 
to  set  fire  to  the  goods.  While  mineral  oils  are  free  from  this 
objection,  they  afford  a  ready  fuel,  and  their  vapors  aid  in  the 
actual  starting  of  the  flame.  In  waterproofing  compositions 
the  chief  danger  arises  from  the  use  of  linseed  oil  which  while 
alone  is  readily  sensitive  to  oxidation  and  consequent  heating, 
has  this  liability  increased  by  the  use  of  materials  on  the  fabric 
which  promote  its  absorption  of  oxygen.^  Thus  by  the  presence 
of  true  oxidants,  catalytic  agents  of  oxidation  and  the  porous 
character  of  the  oiled  material,  grave  risk  is  at  times  encoun- 
tered of  the  complete  destruction  of  the  goods.  This  is  more 
likely  to  happen  during  the  waterproofing  of  the  material  or 
soon  after. 

While  in  the  operations  of  waterproofing  with  oils  known 
to  be  of  an  oxidizing  nature,  certain  rough  tests  are  made  from 
time  to  time  to  control  the  product  and  to  guard  against  the 
risk  of  inflammability,  there  is  grave  lack  of  a  standard  method 
of  testing  these  fabrics,  or  such  tests  as  are  employed  fail  to 
indicate  with  definiteness  whether  the  fabric  will  be  safe.  For 
this  purpose  no  instrument  is  better  than  the  Mackey  apparatus 
for  testing  the  liability  of  oils  to  spontaneous  combustion,  f 

*  Leipziger  Monatschrift,  1893.  p.  221. 

t  See  Jour.  Soc.  Chem.  Ind.,  1896,  p.  90,  and  1907,  p.  185. 


574  THE  TEXTILE   FIBRES 

This  has  been  found  by  frequent  tests  superior  to  other  types 
of  apparatus  having  the  same  end  in  view. 

The  apparatus  consists  of  a  cylindrical  water-jacketed  metal 
oven  of  the  following  dimensions:  Outside  8  inches  high  and  6 
inches  in  diameter;  inside  7  inches  high  and  4  inches  in  diameter. 
The  vessel  is  sealed  with  a  lid  lined  with  non-conducting 
material  and  having  three  holes,  one  at  the  centre  for  a  thermom- 
eter, and  two  diametrically  opposite  near  the  rim  which  receive 
copper  tubes  of  \  inch  diameter  so  arranged  that  when  the 
lid  is  in  place,  one  tube  enters  the  oven  to  a  depth  of  6  inches, 
while  the  other  rises  to  an  equal  height  above  the  lid.  These 
tubes  assure  a  constant  draft  of  air  through  the  instrument. 
In  common  vertical  axis  with  the  central  hole  there  is  supported 
within  the  oven  a  cylinder  of  wire  gauze  6  inches  long  and  i| 
inches  in  diameter.  The  fabric  which  is  suspected  of  liability 
to  spontaneous  inflammability  is  placed  in  a  finely  chipped 
condition  within  the  cylinder  occupying  the  upper  4!  inches, 
and  the  thermometer  is  so  arranged  that  the  bulb  is  in  the 
centre  of  this  mass.  The  water  is  brought  to  the  boiling- 
point  and  the  cylinder  and  thermometer  are  introduced,  the 
latter  protruding  through  a  cork  placed  in  the  central  hole 
in  the  lid.  The  boiling  temperature  is  maintained  and  the 
thermometer  is  read  at  the  end  of  the  hour  and  every  fifteen 
minutes  thereafter;  noting,  however,  if  between  these  times  a 
maximum  of  rise  is  reached.  The  cylinder  may  be  dispensed  with 
if  a  piece  of  the  fabric  $'  by  36",  be  wrapped  directly  about 
the  thermometer.  If  the  fabric  tested  attains  a  temperature  of 
1 00°  C.  within  an  hour,  or  if  it  reaches  a  temperature  of  120°  C. 
within  an  hour  and  a  half,  it  must  be  considered  as  dangerous. 

12.  Microscopic  Analysis  of  Fabrics. — Hohnel  describes 
the  following  method  employed  for  a  microscopic  examina- 
tion of  textile  fabrics,  where  the  object  is  to  determine  not  only 
qualitatively  the  character  of  fibres  composing  them,  but  also 
their  quantitative  amounts.  With  regard  to  the  preliminary 
qualitative  examination,  there  are  generally  only  a  few  fibres 
to  be  taken  into  consideration,  as  there  seldom  occur  in  the 
same  fabric  more  than  one  to  four  different  kinds  of  fibres. 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         575 

As  a  rule,  the  only  fibres  which  will  be  found  are  cotton,  linen' 
hemp,  jute,  ramie,  sheep's  wool,  goat-hair,  cow-hair,  angora, 
alpaca,  cashmere,  llama,  silk,  and  tussah  silk.  In  woolen 
material  there  are  also  cosmos  and  shoddy  to  be  considered. 

To  undertake  the  examination,  cut  off  a  sample  of  the  mate- 
rial 2  to  3  sq.cm.  in  size,  and  separate  this  into  its  warp-  and 
filling-threads.  The  sample  must  be  of  sufficient  size  to  include 
all  of  the  different  kinds  of  yarns  employed  in  the  weave.  Con- 
sequently, in  the  case  of  large  patterns,  it  has  to  be  rather  large. 
The  warp-  and  filling-threads  are  laid  next  to  each  other,  and 
one  of  each  kind  is  selected  to  serve  for  further  examination. 
In  the  simplest  case  there  is  only  one  kind  of  warp-thread  and 
one  kind  of  filling  present,  which  necessitates,  therefore,  the 
examination  of  only  two  different  yarns.  In  complicated  cases 
there  may  be  as  many  as  ten,  or  even  more,  different  yarns  to 
analyze.  In  woolen  fabrics  there  will  frequently  be  found 
yarns  which  are  composed  of  two  or  three  different  threads 
twisted  together;  these  must  be  untwisted  and  each  separate 
yarn  examined  by  itself.  In  order  to  attain  satisfactory  results, 
the  operator  must  be  sufficiently  skilled  in  the  microscopy  of 
the  fibres  to  be  able  to  recognize  with  certainty,  under  a  low 
magnification,  the  different  fibres  liable  to  be  found.  By  a 
low  magnification  is  meant  one  of  fifty  to  sixty  times.  A  much 
higher  power  cannot  be  used  in  the  examination  of  fabrics,  for 
hundreds  or  even  thousands  of  fibres  have  to  be  taken  into 
consideration.  From  ten  to  twenty  fibres,  or  perhaps  more, 
should  be  obtained  in  the  field  at  the  same  time,  and  it  is  neces- 
sary to  be  able  to  promptly  recognize  the  different  ones.  With 
a  higher  magnification,  it  is  true,  the  single  fibres  can  be  better 
recognized,  but  the  general  view  is  then  lost,  and  there  is  dan- 
ger in  overlooking  whole  bundles  of  fibres.  If  the  observer 
finds  a  fibre  which  cannot  be  recognized  with  sufficient  accuracy 
by  means  of  the  low  .power,  it  is  a  simple  matter  to  so  change 
the  objective  as  to  increase  the  magnification  to  allow  of  the 
necessary  observations  to  be  made,  and  then  to  proceed  again 
with  the  examination  under  the  lower  power. 

Dark-colored  material  often  consists  for  the  most  part  of 


576  THE  TEXTILE  FIBRES 

threads  which,  on  microscopic  examination,  appear  quite  opaque, 
hence  dark  and  structureless.  Therefore  it  will  frequently 
be  necessary  to  remove  the  dyestuff,  at  least  in  part,  which  is 
usually  done  by  boiling  in  acetic  acid,  hydrochloric  acid,  dilute 
caustic  alkali,  potassium  carbonate,  etc.,  until  sufficiently  light 
in  appearance. 

In  the  case  of  very  accurate  examinations,  each  different 
kind  of  thread  must  be  examined  separately,  and  the  number 
of  fibres  composing  it,  together  with  their  kind  and  color,  must 
be  noted.  In  order  to  show  the  detail  and  scope  of  such  an 
examination,  the  following  example  is  given:  On  unravelling 
a  sample  four  different  warp-threads  and  one  filling-thread 
were  obtained.  One  of  the  warp-threads  was  composed  of 
two  yarns  twisted  together  one  of  which  was  black  (Kid)  and 
the  other  white  (Kib).  Two  warp-threads  were  dark  blue  (K%  and 
Kz)  and  the  fourth  was  a  gray  mix  (K±) ;  the  filling-thread  (E) 
was  blue.  On  examination  the  following  results  were  obtained. 

K\a  showed  85  shoddy  fibres  (mostly  black,  some  yellow  and 
red  and  even  isolated  green  fibres  of  wool,  and  13  cotton  fibres). 

K\b  showed  31  pure  white  wool  fibres. 

K2  and  K%,  respectively,  showed  46  and  53  pure  blue  wool 
fibres. 

K±  showed  60  shoddy  fibres,  of  which  32  were  mostly  gray  or 
black  wool  fibres,  and  28  were  gray  cotton  fibres. 

E  showed  60  blue  wool  fibres. 

Therefore  in  this  sample,  including  4  warp-  and  4  filling- 
threads,  there  would  be  85+31+46  +  53+60  =  275  single-warp 
fibres;  and  60X4  =  240  filling  fibres;  or  515  single  fibres  alto- 
gether. Of  these  3 1  were  cotton,  which  were  found  in  the  shoddy, 
the  latter  comprising  145  fibres  in  all.  Hence  in  a  sample  of 
this  piece  of  goods  containing  equal  lengths  of  warp  and  weft, 
there  are  41  cotton  fibres,  104  shoddy  wool  fibres,  and  370  pure 
wool  fibres,  from  which  the  respective  percentages  would  be: 

Per  Cent. 

Cotton 8.0 

Shoddy  wool 20 . 2 

Pure  wool 71.8 


ANALYSIS  OF  TEXTILE   FABRICS  AND  YARNS         577 

This,  of  course,  only  gives  the  relative  percentages  of  the 
number  of  fibres;  if  it  is  desired  to  reach  an  approximate  idea 
of  the  proportions  by  weight,  then  micrometric  measurements 
must  be  made  of  the  wool  and  cotton  fibres  occurring  in  the 
sample.  In  consideration  of  the  fact  that  wool  possesses  about 
twice  the  cross-section  of  cotton,  it  becomes  a  rather  easy 
matter  to  calculate  the  ratio  between  the  two,  by  means  of  which 
the  percentage  by  weight  can  be  readily  obtained,  provided 
that  the  specific  gravity  of  wool  is  taken  to  be  about  the  same 
as  that  of  cotton,  which  is  approximately  true. 

13.  Determination  of  the  Size  of  Yarns. — Yarns  are  classified 
as  coarse  or  fine  according  to  their  relative  thickness  or  weight 
per  given  length.  This  is  known  as  the  size  or  count  of  the  yarn. 
There  are  a  large  number  of  different  standards  employed  for 
determining  the  numbers  of  yarns  depending  on  the  character 
of  the  fibre  (wool,  silk,  cotton,  linen,  etc.)  and  on  the  locality 
in  which  the  yarns  are  spun.  The  English  system  for  number- 
ing woolen,  worsted,  and  cotton  yarns  is  the  most  extensively 
employed  throughout  the  world,  while  for  the  numbering  of 
silk  yarns  the  French  system  is  used  chiefly  on  the  European 
continent. 

The  determination  of  the  count  of  a  yarn  is  based  upon  one 
of  two  methods:  (a)  the  weight  of  a  definite  length  of  the  yarn, 
in  which  case  the  weight  of  the  standard  length  is  designated 
as  the  yarn  number;  this  method  is  principally  employed  in 
the  case  of  silk;  (b)  the  length  of  a  definite  weight  of  the  yarn, 
in  which  case  the  numbers  will  depend  on  the  system  of  weights 
adopted;  the  English  system  employing  the  English  weights, 
and  the  metric  system  using  the  metric  weights.  This  method 
is  used  for  yarns  of  wool,  cotton,  spun  silk,  linen,  etc. 

In  the  English  standards  for  various  fibres,  No.  i  yarn  has 
the  following  yards  per  pound: 

Cotton 840  yards 

Linen 300     ' ' 

Woolen 1600     " 

Worsted 560     ' ' 

Spun  silk 840     ' ' 


578 


THE  TEXTILE    FIBRES 


The  following  table  gives  the  equivalent  counts  of  the  dif 
ferent  yarns  for  the  same  weight  per  yard: 


Cotton  (Hanks 
of  840  Yards.) 

Linen  (Cuts  of 
300  Yards.) 

Woolen  (Runs 
of  1600  Yards). 

Worsted  (Hanks 
of  560  Yards). 

Thrown  Silk 
(Yards  in  One 
Ounce.) 

I 

2.8 

o  525 

1-5 

52.5 

0-357 

I 

0.187 

0-54 

18.7 

i.  9 

5-3 

I 

2.85 

100.  O 

0.66 

1.85 

0.346 

I 

34-6 

0.019 

o  •  °53 

0.01 

0.029 

i 

• 

The  apparatus  employed  for  determining  the  weight  of  the 
prescribed  length  of  yarn  may  be  an  ordinary  balance  or  scales, 
though  special  yarn  balances  are  made  with  arcs  variously 
graduated  according  to  the  system  of  counts  desired,  thus  giving 
the  size  of  the  yarn  as  a  direct  reading. 

It  is  to  be  regretted  that  there  is  not  a  uniform  system  for 
numbering  yarns,  for  at  the  present  time  the  matter  is  in  a  rather 
chaotic  state,  each  fibre  having  its  own  special  system,  and  these 
systems  also  varying  widely  in  different  localities.  There  have 
been  many  attempts  recently  made  to  introduce  the  metric 
system  of  numbering  as  being  a  convenient  and  logical  one, 
but  without  any  marked  degree  of  success.  It  has  also  been 
proposed  to  adopt  a  simple  English  standard  in  which  the  unit 
of  length  would  be  1000  yards  and  the  unit  of  weight  i  pound, 
then  the  count  of  the  yarn  would  indicate  the  number  of  1000 
yard  units  contained  in  one  pound  by  weight.  Such  a  system 
would  greatly  simplify  the  present  complicated  methods  of 
yarn  counting.  But  owing  to  the  fact  that  reels  and  testing 
apparatus  have  been  made  in  conformity  with  the  present 
standard  sizes,  and  that  the  prices  paid  for  the  manufacture 
of  yarns  are  based  on  specified  numbers,  any  radical  change 
in  the  systems  of  yarn  numbering  would  entail  a  complete 
readjustment  throughout  the  textile  industry;  consequently 
any  attempt  at  sudden  change  of  system  is  doomed  to  failure. 

The  general  principle  underlying  the  determination  of  the 
yarn  number  is  to  reel  off  the  yarn  in  hanks  of  a  definite  number 
of  yards  (English  system)  or  meters  (Metric  system),  and  then 


ANALYSIS   OF  TEXTILE   FABRICS  AND  YARNS         579 

determine  the  weight  of  these  hanks;  the  number  of  such 
hanks  required  to  give  the  standard  weight  determines  the 
count  of  the  yarn.* 

(a)  Cotton  Yarns. — The  number  or  count f  of  cotton  yarn 
is  determined  by  the  number  of  hanks  of  840  yards  each  con- 
tained in  i  pound.  This  is  the  basis  of  the  English  system 
and  is  in  use  throughout  England,  America,  Germany,  India 
and  Switzerland.  The  French  method  of  numbering  is  based 
on  the  decimal  system,  and  the  count  means  the  number  of 
hanks  each  1000  metres  in  length  required  to  weigh  500  gms. 
To  pass  from  the  French  (metric)  system  into  the  English,  and 
conversely,  use  the  following  factors: 

English  count  =  French  countXi.iS. 
French  count  =  English  count  X  0.847 

The  Belgian  method  of  counting  is  to  use  the  number  of  840-yard 
hanks  in  500  grams.  The  Austrian  system  is  the  number  of 
hanks  of  950  ells  each  contained  in  $00  gms.  Doubled  or  twisted 
yarns  are  designated  in  the  same  manner  as  single  yarns,  except 
that  the  number  of  threads  is  also  given,  for  instance,  if  two 
single  threads  of  count  20  are  twisted  together,  the  yarn  is 
described  as  2-2o's  or  ?\,  or  20/2;  a  three-ply  yarn  would  be 
3  -2o's,  or  -£Q  or  20/3,  etc.  According  to  the  number  of  threads 
twisted  together,  yarns  will  lose  from  2.5  to  6  per  cent  of  their 
length  in  doubling,  and,  of  course,  become  correspondingly 
thicker.  Yarns  containing  more  than  two  single  threads  are 
known  as  sewing  twist  or  cord. 

In  order  to  avoid  the  necessity  of  reeling  off  such  a  large 
quantity  as  840  yards,  the  hank  is  divided  into  7  leas  of  120 
yards  each.  The  standard  reel,  employed  has  a  circumference 

*  The  number  of  yards  of  the  various  yarns  that  weigh  the  following  amount 
in  grains,  is  the  English  count  of  that  yarn: 

Cotton  yarn 8 . 330  grains 

Woolen     "    .t 4-375      " 

Worsted   "    12. 500      ' ' 

Linen         '    23.330      " 

f  In  England  the  count  of  yarn  is  frequently  called  the  "grist." 


580 


THE  TEXTILE   FIBRES 


of  i^  yards  (54  inches),  hence  a  lea  (or  lay)  is  equivalent  to  80 
turns  of  the  reel.     We  have  the  following  relations: 

i  thread  =  i|  yards. 
80  threads  =  i  lea  =  1 20  yards. 
7  leas  =  i  hank  =  840  yards. 

COMPARATIVE  TABLE  OF  FRENCH  AND  ENGLISH  YARN  NUMBERS 


French. 

English. 

French. 

English. 

French. 

English. 

French. 

English. 

I 

1.18 

II 

12.  I 

21 

24.8 

32 

37-8 

2 

2.23 

12 

14.2 

22 

26.0 

34 

40.  i 

3 

3-54 

13 

15-3 

23 

27.2 

36 

42-5 

4 

4-72 

14 

I6.5 

24 

28.3 

38 

44-8 

5 

5-90 

15 

17.7 

25 

29-5 

40 

47-2 

6 

7.8 

16 

l8.Q 

26 

30.7 

45 

52-1 

7 

8.26 

17 

2O.  I 

27 

31-8 

50 

59-0 

8 

9-44 

18 

21.2 

28 

33-o 

55 

64.9 

9 

10.62 

19 

22.4 

29 

34-2 

60 

70.8 

10 

1  1.  80 

20 

23-6 

30 

35-4 

The  finest  number  of  cotton  yarn  to  be  met  with  in  commerce 
is  240;  numbers  higher  than  this  have  rarely  been  spun  in 
any  amounts.  Up  to  2o's  the  counts  rise  by  single  numbers, 
such  as  i,  2,  3,  4,  5,  etc.  Beyond  2o's  it  is  customary  to  make 
use  of  only  the  even  numbers,  like  22,  26,  30,  etc.  Above  6o's 
the  numbers  rise  by  5,  such  as  65,  70,  75,  etc.,  and  above  loo's 
they  rise  by  10.  The  coarsest  yarns  used  for  weaving  are  6's 
and  8's;  though  yarns  of  coarser  count  than  these  are  employed 
for  lamp-wicks,  cordage,  etc.* 

*  The  following  variations  above  and  below  the  exact  standard  representing 

the  counts  of  various  yarns  are  allowed: 

Per  Cent. 

1.  Cotton  yarns  Nos.  i  to  10  English 2.5 

Waste  yarn,  including  so-called  "imitation"  yarns,  up 

to  No.  6 4.0 

Cotton  yarns  Nos.  n  to  20 2.0 

Nos.  21  to  40 2.5 

above  No.  40 3.0 

2.  Worsted  yarn 1.5 

3.  Carded  yarn 2.5 

Shoddy  from  wool 4.0 

4.  Mixed  wool  and  cotton  yarn *. ...  2.5 

"         "         silk 1.5 

5.  Linen  yarn 2.5 

6.  Jute  yarn 3.0 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         581 


The  following  table  shows  the  comparative  length  of  dif- 
ferent counts  of  cotton  yarn: 


No. 

Yards 
per 
Pound. 

Weight 
per   1000 
Yards, 
Ozs. 

No. 

Yards 
per 
Pound. 

Weight 
per  1000 
Yards, 
Ozs. 

No. 

Yards 
per 
Pound. 

Weight 
per  1000 
Yards, 
Ozs. 

4 

3,360 

4.76 

16 

13440 

1.  19 

36 

30,240 

0.517 

6 

5^40 

3-l8 

18 

15,120 

1.065 

40 

33,600 

0.476 

8 

6,720 

2-38 

20 

16,800 

0.952 

44 

36,960 

0-433 

10 

8,400 

I.QO 

24 

20.l6o 

0-795 

50 

42,000 

0.380 

12 

I0,o8o 

1-59 

28 

23,520 

0.695 

60 

50,440 

0.317 

14 

11,760 

i-39 

32 

26,880 

0-595 

80 

67,200 

0.238 

The  following  table  gives  the  counts  of  cotton  yarns  by  the 
weight  in  grains  of  i  skein  of  120  yards:* 


1  20  Yards 
Weigh 
Grains. 

Count 
of 

Yarn. 

1  20  Yards 
Weigh 
Grains. 

Count 
of 
Yarn. 

1  20  Yards 
Weigh 
Grains. 

Count 
of 
Yarn. 

120  Yards 
Weigh 
Grains. 

Count 
of 
Yarn. 

I 

IOOO 

15 

67 

27 

37 

50 

2O 

2 

500 

15-5 

65 

27-5 

36.5 

52 

19 

3 

333 

16 

63 

28 

36 

54 

l8-5 

4 

250 

16.5 

6l 

28.5 

35 

56 

18 

5 

200 

17 

59 

29 

34-5 

58 

17 

5-5 

181 

17-5 

57 

29-5 

34 

62 

16 

6 

167 

18 

56 

30 

33-5 

66 

15 

6-5 

154 

18-5 

54 

30-5 

33 

70 

U 

7 

143 

19 

53 

31 

32-5 

74 

13-5 

7-5 
5    . 

133 

I25 

19-5 
20 

5i 
50 

31-5 
32 

32 
3i 

78 
83 

13 

12 

8-5 

118 

20.5 

49 

33 

30 

9i 

II 

0 

in 

21 

48 

34 

29  5 

IOO 

IO 

95 

105 

21-5 

47 

35 

29 

in 

9 

10 

100 

22 

45 

36 

28 

125 

8 

10.5 

95 

22.5 

44 

37 

27 

143 

7 

ii 

9i 

23 

43 

38 

26 

167 

6 

ii  5 

87 

23-5 

42-5 

39 

25-5 

200 

5 

12 

83 

24 

42 

1     40 

25 

250 

4 

12-5 

80 

24-5 

4i 

1     4i 

24-5 

334 

3 

13 

77 

25 

40 

42 

24 

500 

2 

13-5 

74 

25  -5 

39 

44 

23 

IOOO 

I 

14 

7i 

26 

38 

46 

22 

14-5 

69 

26.5 

37-5 

48 

21 

*  A  short  method  of  determining  the  count  of  cotton  yarn  when  only  a  short 
length  is  available  is  to  weigh  off  in  grains  12  yards  of  the  yarn,  and  divide  this 
number  into  100.  Thus,  if  12  yards  weigh  5  grains,  the  count  is  100-7-5  =  20. 


582 


THE  TEXTILE   FIBRES 


(b)  Woolen  Yarns. — The  English  system  numbering  of 
woolen  yarns  is  based  on  the  number  of  "  runs  "  in  one  pound; 
a  "  run  "  is  1600  yards.*  The  following  table  gives  the  "  runs  " 
or  count  of  woolen  yams  by  the  weight  in  grains  of  20  yards. 


20  Yards 
Weigh 
Grains. 

i 

tfl  j*  en 
0 

c 

3 

||| 
8 

i 

o 

<N 

I 
M 

•2.C  2 

C.M.S 

o 

<N 

c 

3 

20  Yards  i 
Weigh 
Grains. 

c 

3 
ttl 

I 

87.5 

18 

4-9 

35 

2.5 

52 

1.68 

69 

1.27 

86 

I  .02 

2 

43-7 

19 

4-6 

36 

2.4 

53 

1-65 

70 

•25 

87 

1  .01 

3 

29.2 

20 

4-4 

37 

2.36 

54 

1.62 

71 

•23 

88 

0.99 

4 

21.9 

21 

4-2 

38 

2.30 

55 

i-59  ! 

72 

.  22 

89 

0.98 

5 

17-5 

22 

4.0 

39 

2.24 

56 

1-56  | 

73 

.20 

90 

O-97 

6 

14.6 

23 

3-8 

40 

2.19 

57 

J-54 

74 

.18 

91 

0.96 

7 

12.5 

24 

3-6 

41 

2.13 

58 

i  -5i 

75 

•17 

92 

0-9.S 

8 

10.9 

25 

3-5 

42 

2.08 

59 

1.48 

76 

•15 

93 

0.94 

9 

9-7 

26 

3-4 

43 

2.03 

60 

1.46 

77 

•14 

94 

o-93 

10 

8.7 

27 

3-2 

44 

•99 

61 

i-43 

78 

.  12 

95 

0.92 

ii 

7-9 

28 

3-i 

45 

•94 

62 

1.41 

79 

.  II 

96 

0.91 

12 

7-3 

29 

3-o 

46 

.90 

63 

1-38 

80 

.09 

97 

O.QO 

13 

6-7 

30 

2.9 

47 

.86 

64 

i-37 

81 

.08 

98 

0.89 

14 

6.2 

31 

2.8 

48 

.82 

65 

i-35 

82 

.07 

99 

0.88 

15 

5-8 

32 

2-7 

49 

•79 

66 

i-33 

83 

•05 

IOO 

0.87 

16 

5-5 

33 

2.6 

50 

•75 

67 

1.31 

84 

•0-1 

17 

5-2 

34 

2.6 

51 

.72 

68 

1.29 

85 

•03 

In  the  metric  or  international  system  the  count  of  woolen 
yarn  is  the  number  of  hanks  of  1000  metres  weighing  i  kilogram. 

In  the  American  system  the  "  cut  "  is  frequently  used  for 
the  count  of  woolen  yarns.  This  is  based  on  the  number  of 
cuts  of  300  yards  in  one  pound.  In  the  grain  system  the  count 
is  designated  by  the  weight  in  grains  of  20  yards. 

(c)  Worsted  Yarns. — The  numbering  of  worsted  yarns  by 
the  English  system  is  based  on  the  number  of  "  hanks  "  of 
560  yards  in  one  pound,  f  The  following  table  gives  the 

*  As  this  is  equivalent  to  100  yard  lengths  to  one  ounce,  the  run  system  is 
very  convenient  for  calculating  the  weight  of  yarns  in  ounces;  thus,  IT  runs  is 
equivalent  to  125  yards  per  ounce. 

t  The  count  of  worsted  yarns,  where  only  short  lengths  are  available,  may 
be  determined  by  dividing  150  by  the  weight  in  grains  of  12  yards;  hence  if  12 


ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         583 


count  of  worsted  yarns  by  the  weight  in  grains  of  20  yards: 


W    _i    W 

•E-S.S 

rt'S  £ 
^0 

M 

*jj 

6> 

20  Yards 
Weigh 
Grains. 

oS 
di* 

20  Yards 
Weigh 
Grains. 

*§ 

6> 

•g-ai 

ca'S  a 

*£o 

§ 

og 

6> 

111 
**& 

N 

*l 

6> 

111 

5» 

« 

';! 
«**  ** 

o  a 

r 

I 

250 

19 

13.16 

37 

6.76 

55 

4-55 

73 

3-42 

91 

2-75 

2 

125 

2O 

12.50 

38 

6.58 

56 

4-46 

74 

3.38 

92 

2.72 

3 

83-33 

21 

11.90 

39 

6.41 

57 

4-39 

75 

3-33 

93 

2.69 

4 

62.50 

22 

11.36 

40 

6-25 

58 

4-31 

76 

3-29 

94 

2.66 

5 

50 

23 

10.87 

4i 

6.  10 

59 

4.24 

77 

3-25 

95 

2.63 

6 

41.67 

24 

10.42 

42 

5-95 

60 

4.17 

78 

3.21 

96 

2.60 

7 

35-71 

25 

10 

43 

5-8i 

61 

4.  10 

79 

3-17 

97 

2-58 

8 

31-25 

26 

9.62 

44 

5-68 

62 

4-03 

80 

3-12 

98 

2-55 

9 

27.78 

27 

9.26 

45 

5-56 

63 

3-97 

81 

3-09 

99 

2.52 

10 

25 

28 

8-93 

46 

5-43 

64 

3-9i 

82 

3-05 

IOO 

2.50 

ii 

22.73 

29 

8.62 

47 

5-32 

65 

3-85 

83 

3.01 

105 

2.38 

12 

20.83 

30 

8-33 

48 

5-21 

66 

3-79 

84 

2.98 

no 

2.27 

13 

19.23 

31 

8.06 

49 

5-io 

67 

3-73 

85 

2-94 

115 

2.17 

14 

17.86 

32 

7.81 

50 

5-oo 

68 

3-68 

86 

2.91 

120 

2.08 

15 

16.67 

33 

7.58 

5i 

4.90 

69 

3-62 

87 

2.87 

125 

2.OO 

16 

15.62 

34 

7-35 

52 

4.81 

70 

3-57 

88 

2.84 

150 

1.67 

i? 

14.71 

35 

7-i4 

53 

4.72 

7i 

3-52 

89 

2.81 

175 

i-43 

18 

13-89 

36 

6.94 

54 

4-63 

72 

3-47 

90 

2.78 

2OO 

1.25 

(d)  Silk  Yarns. — The  fineness  or  size  of  raw  silk  thread  is 
expressed  by  a  number  known  as  litre  (in  French)  or  titolo  (in 
Italian);  this  gives  the  number  of  units  of  certain  weight 
(denier  =  5 3. 1 3  mgms.)  a  skein  of  certain  length  will  weigh. 
Several  different  standards  are  in  use  in  Europe  at  the  present 
time,  among  which  are  the  following: 


Weight  in  Grams. 

Length  in  Metres. 

Denier  (Italian,  legal)  
Denier  (Milan)  

0.05 
O.O5I 

450 
476 

Denier  (Turin)  

0.0534 

476 

Old  denier  (Lyons) 

o  os3i 

4?6 

New  denier  (Lyons)  

0.0531 

500 

Denier  (international)  

0.05 

500 

yards  weigh  5  grains,  the  count  would  be  150-5-5  =  30.     Also  this  formula  may 
be  used: 

yards  weighed 


Count 


0.08  weight  in  grains 


584  THE  TEXTILE  FIBRES 

The  titre  is  usually  expressed  in  the  form  of  a  fraction, 
representing  limits  of  variation,  as  all  skeins  are  not  of  abso- 
lutely the  same  size.  A  silk  marked  18/20,  for  instance,  would 
mean  that  it  varied  from  18  to  20  deniers. 

The  international  denier  *  may,  perhaps,  be  more  conven- 
iently denned  as  being  the  weight  (in  grams)  of  10,000  metres. 
The  basis  for  the  sizing  of  thrown  silk  in  England  and  the 
United  States  is  the  weight  in  drams  of  1000  yards.  To  convert 
this  weight  into  deniers,  it  is  necessary  to  multiply  by  the 
factor  33.36.  For  example,  if  1000  yards  of  silk  weigh  3  drams, 
it  would  be  equivalent  to  33.36X3  =  100.08  deniers.  In  France 
the  size  of  the  silk  is  usually  expressed  in  terms  of  the  old  denier, 
which  was  the  weight  in  deniers  of  400  French  ells.  The  latter 
length  is  equivalent  to  476  metres,  and  the  denier  is  equal  to 
0.05313  gm.f  Hence,  to  obtain  the  size  in  deniers  according 
to  this  system,  multiply  the  weight  in  grams  of  476  metres  by 
the  factor  18.82  (  =  1-7-0.05313).  For  example,  if  476  metres 
of  silk  weigh  5  grams,  this  would  be  equivalent  to  5  X  18.82  =  94.1 
deniers.  To  obtain  the  deniers  under  the  new  measure,  the 

*  Adopted  by  the  International  Yarn  Numbering  Congress,  held  in  Vienna 
in  1873. 

t  The  denier  is  supposed  to  be  derived  from  the  weight  of  a  Roman  coin  of 
small  value  called  denarius.  The  abbreviation  for  pence  (</)  in  the  English 
monetary  system  is  derived  also  from  this  word. 

The  origin  and  history  of  the  denier  are  quite  interesting.  The  denier  was 
a  small  coin,  originally  of  silver,  and  was  introduced  into  Caul  by  the  Romans, 
probably  about  the  time  of  Caesar's  Gallic  wars.  The  value  of  this  piece  was 
about  1 6  cents.  Later,  the  name  denier  was  applied  to  both  gold  and  copper 
coins  as  well.  It  is  claimed  that  it  was  the  latter  which  was  originally  used  as  a 
weight,  but  this  is  uncertain.  However,  the  denier,  whichever  it  was,  weighed 
24  grains  Poids  de  Marc.  The  old  method  of  grading  silk  was  to  take  80  skeins 
of  1 20  aunes  (giving  a  total  length  of  9600  aunes)  and  find  their  weight  in  deniers. 
Toward  the  end  of  the  eighteenth  century,  one  Matley,  observing  that  the  grain 
was  i /24th  of  the  denier,  conceived  the  idea  of  taking  skeins  of  400  aunes^(or 
i /24th  of  9600)  and  weighing  these  in  grains,  thus  preserving  the  ratio.  He 
made  a  machine  for  measuring  these  skeins  of  400  aunes.  The  trade  accepted  the 
change,  but  could  not  get  rid  of  the  old  term  denier,  which  now  became  fastened 
to  the  new  grain  weight,  so  that  the  denier  weight  as  we  know  it  to-day,  is  really 
a  i-grain  Poid  de  Marc,  and  i/24th  of  its  original  value.  The  present  denier 
has  a  value  of  0.0531  gram  =  0.833  grain,  and  the  400  aunes  skein  is  equal  to 
476  metres  =  52o  yards  and  20  inches. 


ANALYSIS  OF  TEXTILE   FABRICS  AND    YARNS        585 


weight  in  grams  of  500  metres  is  multiplied  by  the  factor 
18.82.  The  legal  measure  in  France  of  the  size  of  silk  is  repre- 
sented by  the  weight  in  grams  of  500  metres,  but  it  is  probably 
more  usual  to  express  the  size  in  terms  of  deniers.  To  convert 
the  new  denier  into  the  old  denier,  multiply  by  the  factor 

0.952  f  =       )•     The  denier  on  the  old  system  may  be  converted 

into  the  international  measure  (based  on  a  weight  of  0.05 
gram  for  a  length  of  500  metres)  by  multiplying  by  the 
factor  1.116;  and,  inversely,  the  international  denier  may 
be  converted  into  the  old  system  denier  by  multiplying  by 
the  factor  0.896. 

The  following  tables  show  the  relations  between  the  different 
measures  of  the  French  scale: 


Legal 
Titre. 

New 

Denier. 

Old 
Denier. 

Internat. 
Denier. 

Legal 
Titre. 

New 
[Denier. 

Old 
.Denier. 

Internat. 
Denier. 

Weight 
of  500 
Metres  in 
Grams. 

Weight 
of  500 
Metres  in 
Oeniers. 

Weight 
of  476 
Metres  in 
Deniers. 

Weight 
of  10,000 

Metres  in  ! 
Grams. 

Weight 
of  500 
Metres  in 
Grams. 

Weight 
of  500 
Metres  in 
Deniers. 

Weight 
of  476 
Metres  in 
Deniers. 

Weight 
of  10,000 
Metres  in 
Grams. 

O.I 

1.88 

1.78 

2 

4-1 

77.16 

73-45 

82 

0.2 

3-76 

3.58 

4 

4-2 

79-05 

75-25 

84 

0-3 

5-64 

5.36 

6 

43 

80.93 

77.04 

86 

0-4 

7-52 

7.16 

8 

4-4 

82.81 

78.83 

88 

0-5 

9.41 

8-95 

10 

4-5 

84.69 

80.62 

90 

0.6 

11.29 

10.73 

12 

4-6 

86.58 

82.42 

92 

0.7 

13-17 

12-53 

14 

4-7 

88.46 

84.21 

94 

0.8 

I5-05 

14.32 

16 

4-8 

90.34 

86.00 

96 

o-9 

16.93 

i6.n 

18 

4-9 

92.22 

87.79 

98 

i  .0 

18.82 

17.91 

20 

5-0 

94.10 

89.58 

IOO 

.  i 

2O.  70 

19.70 

22 

5-i 

95  99 

91.38 

IO2 

.2 

22.58 

21.49 

24 

5-2 

07.87 

93-17 

104 

•3 

24.46 

23.28 

26 

5-3 

99-75 

94-96 

106 

.4 

26-35 

25.08 

28 

5-4 

101.63 

96.75 

108 

•5 

28.23 

27-87 

30 

5-5 

103.51 

98.54 

no 

.6 

30.11 

28.66 

32 

56 

105.40 

100.33 

112 

•  7 

31-99 

30.45 

34 

5-7 

107.  28 

IO2.I2 

114 

.8 

33.87 

32.24 

36 

5-8 

109.16 

103.92 

116 

•9 

35-76 

34-04 

38 

59 

i  i  i  .  04 

105.71 

118 

2.0 

37-64 

35.83 

40 

6.0 

112.93 

107.50 

1  20 

586 


THE  TEXTILE   FIBRES 


Legal 
Titre. 

New 
Denier. 

Old 
[Denier. 

Internat.    i 
Denier. 

Legal 
Titre. 

New 
Denier. 

Old 
Denier. 

Internat. 
Denier. 

Weight 
of  500 
Metres  in 
Grams. 

Weight 
of  500 
Metres  in 
Deniers. 

Weight 
of  476 
Metres  in 
Deniers. 

Weight 
of  10,000    i 
Metres  in 
Grams. 

Weight 
of  500 
Metres  in 
Grams. 

Weight 
of  500 
Metres  in 
Deniers. 

Weight 
of  476 
Metres  in 
Deniers. 

Weight 
of  10,000 
Metres  in 
Grams. 

2.  I 

39-52 

37.62 

42                  6.1 

114.81 

109.29 

122 

2.  2 

41.40 

39-41 

44                 6.2           116.69 

IIl.oS 

124 

2-3 

43-29 

41  .20 

46                 6.3           118.57 

112.87 

126 

2.4 

45-17 

43-00 

48                6.4 

120.45 

i  14  .  66 

128 

2-5 

47-05 

44-78 

50                6.5 

122.34 

116.46 

130 

2.6 

48.93 

46.57 

52                6.6       '  124.22 

118.25 

132 

2.7 

50.81 

48.57 

54 

6-7 

126.  10 

i  20  .  04 

134 

2.8 

52.70 

50.16 

56, 

6.8 

127.98 

121.83 

136 

2.9 

54-58 

51-95 

58                6.9 

129.87 

123-63 

138 

3-o 

56.46 

53-74 

60 

7-o 

131-75 

125-42 

140 

3-i 

58.34 

55-54 

62 

7-i 

I33-63 

127.  21 

142 

3-2 

3-3 

60.  22 
62.  II 

57-33 
59-12 

64                7.2 
66        ||       7-3 

I35-5I 
137-39 

I29.OO 
130.80 

144 
146 

3-4 

63-99 

60.91 

68                7-4' 

139.28 

132.59 

148 

**•  5 

65.87 

62.70 

70                7-5 

141  .  16 

134-39 

150 

3-6 

67-75 

64-49 

72                7.6 

143-04 

I36.I/               152 

3-7 

69.64 

66.  29 

74                7-7 

144-92 

137.96 

154 

3-8 

71.52 

68.08 

76                7-8 

146.80 

139-70 

156 

3-9 

73-40 

69.87 

78 

7.9       '  148.69 

141.56 

158 

4-0 

75-28 

71.66 

80 

8.0 

150.57 

143-34 

1  60 

8.1 

152.45 

I45-I3 

162 

IO.  I 

190.09 

180.97 

202 

8.2 

154-33 

146.92 

164 

10.2 

191.98 

182.76 

2O4 

8-3 

156.22 

148.71 

1  66 

10.3 

193.86 

184.55 

206 

8.4 

158.10 

150.50 

1  68 

10.4 

195-74 

186.35 

208 

8-5 
8.6 

159.98 

161.86 

152  30 
154.08 

170 
172 

10-5 

10.6 

197.62 
I99-5I 

I88.I4               210 
189.93               212 

8-7 

163-74 

155-88 

174 

10.7 

201.39 

101.72               214 

8.8 

165-63 

157-67 

176 

10.8 

203.27 

193-51 

216 

8.9 

167.51 

I59-46 

178 

10.9 

205.15 

I95-30 

218 

9.0 

169.39 

161.25 

1  80 

H  .0 

207  .  03 

179.10 

22O 

9.1 

171.27 

163.04 

182 

II  .  I 

208.92 

198.09 

222 

9-2 

173.16 

164.84 

184 

11.2 

210.80 

200.68 

224 

9-3 

175-04 

166.63 

186 

ii.  3 

212.68 

202.47 

226 

9-4 

176.92 

168.42 

1  88 

11.4 

214-56 

204  .  26 

228 

95 

178.80 

170.21 

190 

n-5 

216.45 

206  .  06 

230 

9-6 

180.68 

172.00 

192 

n.  6 

218.33 

207.85 

232 

9-7 

182.57 

173-80 

194 

ii.  7 

220.  21 

209  .  64 

234 

9.8 

184-45 

i  75  •  59 

196 

11.  8 

222.09 

211.43 

236 

9-9 

186.33 

177  38 

198 

11.9 

223-97 

213.22 

238 

IO.O 

188.21 

179.17 

200 

12.0 

225.86 

215.01 

240 

ANALYSIS  OF  TEXTILE  FABRICS  AND   YARNS        587 


The  following  table  shows  the  comparison  between  drams, 
grams,  and  deniers: 


Drams. 

Grams. 

Deniers. 

Drams. 

Grams. 

Deniers. 

0.0299 

0.05313 

1.0 

2.50 

4-43 

83-4 

0.25 

0.44 

8-3 

2-75 

4.87 

91  .6 

0.50 

0.88 

l6.5 

3-oo 

5-3i 

IOO.O 

o  .  568 

i  .00 

18.82 

4.00 

7.09 

133-0 

0.75 

i-33 

25.0 

5-oo 

8.86 

166.0 

1  .00 

1.771875 

33-36 

6.00 

10.63 

199.0 

«->S 

2.  21 

41.6 

7.00 

12.40 

233-o 

i  50 

2.65 

50.0 

8.00 

14.17 

265.0 

i-75 

3.10 

58.3 

9.00 

15-95 

299.0 

2  .00 

3-54 

66.6 

10.00 

17.72 

333-0 

2.25 

3-98 

75-o 

To  convert  the  new  international  titre  into  any  of  the  older 
standards  multiply  by  the  following  factors: 

To  Turin  titre  X  0.8931 

To  Milan  titre  X  0.9315. 

To  French  titre  X  0.8964 

To  Italian  (legal)  and  Swiss  titre  X  0.9000. 

Conversely,  to  convert  any  of  the  above  old  titres  into  the 
new  international  equivalent,  divide  by  the  above  factors. 

For  the  sizing  of  spun  silk  the  unit  of  the  English  scale  is  a 
hank  of  840  yards,  and  the  number  of  such  hanks  in  one  pound 
is  the  count  of  the  yarn.  There  is  a  difference  in  the  counting 
of  doubled  spun  silk  from  that  of  doubled  cotton  yarn,  in  that 
with  cotton  "  2-40*5 "  means  single  4o's  doubled  to  2o's; 
whereas,  with  spun  silk,  "  2-4o's  "  means  single  80 's  doubled  to 
4o's,  and  "  3~4o's  "  would  mean  single  i2o's  tripled  to  40*5,  etc. 

In  France  and  Switzerland  the  number  or  size  of  spun  silk 
indicates  the  number  of  skeins  of  1000  metres  in  i  kilogram. 
To  convert  the  English  number  into  the  French  or  metric 
number  multiply  by  the  factor  1.69;  and  to  convert  the  French 
number  into  the  English  number  multiply  by  the  factor  0.59. 

Sewing  silk  is  numbered  irregularly  by  letters,  OOO,  OO,  O, 
A,  B,  C,  D,  E,  EE,  F,  FF,  G.  The  yards  in  one  ounce  for  the 


588 


THE  TEXTILE   FIBRES 


respective  letters  are  2000,  1600,  1300,  1000,  850,  650,  550,  400, 
330,  262,  212,  and    125. 

In  Europe,  thrown  silk  is  graded  in  the  same  manner  as 
raw  silk,  but  with  American  and  English  throwsters  the  adopted 
custom  of  specifying  the  counts  of  raw  silk  yarns  is  to  give  the 
weight  of  a  hank  of  1000  yards  in  drams  avoirdupois;  thus,  if 
such  a  hank  weighs  5  drams,  it  is  technically  known  as  5-dram  silk. 
The  size  of  yarn  is  always  given  for  the  "  gum  weight;"  that  is, 
its  condition  before  boiling-off.  In  this  latter  process  yarns  lose 
from  15  to  30  per  cent,  according  to  the  class  of  raw  silk  used, 
Chinese  silks  losing  the  most  and  Japanese  and  European  silks 
the  least.  The  following  table  shows  the  number  of  yards  to  the 
pound  and  ounce  of  silk  of  different  dram  sizes.  The  number 
of  yards  per  pound  being  based  on  a  pound  of  gum  silk: 

LENGTH  OF  GUM  SILK  YARN  PER  POUND  AND  PER  OUNCE 


Drams  per 
1000  Yards. 

Yards  per 
Pound. 

Yards  per 
Ounce. 

Drams  per 
1000  Yards. 

Yards  per 
Pound. 

Yards  per 
Ounce. 

I 

256,000 

l6,OOO 

9 

28,444 

,778 

If 

204,800 

12,800 

01 

26,947 

,684 

li 

170,666 

10,667 

IO 

25,600 

,600 

If 

146,286 

9,J43 

n 

23,273 

,455 

2 

I28,OOO 

8,000 

12 

21,333 

-333 

*J 

H3J77 

7,111 

13 

19,692 

,231 

^ 

102,400 

6.400 

14 

18,286 

,143 

2l 

93,09! 

5,818 

15 

17,067 

,067 

3 

85,333 

5,333 

16 

16,000 

,000 

3i 

78,769 

4,923 

17 

15,058 

941 

3* 

73,143 

4,57i 

18 

14,222 

889 

3* 

68,267 

4,267 

19 

13,474 

842 

4 

64,000 

4,000 

20 

12,800 

800 

4i 

60,235 

3,765 

21 

12,190 

762 

4^ 

56,889 

3,556 

22 

11,636 

727 

4i 

53,368 

3,368 

23 

11,130 

696 

5 

51,200 

3,200 

24 

10,667 

666 

5* 

46,545 

2,909 

25 

10,240 

640 

6 

42,667 

2,667 

26 

9,846" 

615 

6J 

39,385 

2,462 

27 

9,481 

592 

7 

36,571 

2,286 

28 

9,143 

57i 

1\ 

34,133 

2,133 

29 

8,827 

55i 

8 

32,000 

2,000 

30 

8-533 

533 

•        8£ 

30,118 

1,882 

ANALYSIS  OF  TEXTILE  FABRICS  AND  YARNS         589 

Another  method  of  sizing  silk  yarns  which  is  sometimes 
used,  is  the  ounce  system.  This  system  is  mostly  used  in  con- 
nection with  other  trades  than  weaving  and  knitting,  and  where 
thick  counts  of  yarn  are  employed.  The  system  is  based  on  the 
weight  in  ounces  of  a  looo-yard  hank.  We  thus  have  three 
methods  of  sizing  thrown  silk: 

i.  Denier  system.        2.  Dram  system.       3.  Ounce  system. 

To  ascertain  the  equivalent  count  of  a  given  yarn  in  any 
of  these  systems,  proceed  as  follows: 

(a)  Denier  to  dram  X  0.058. 

(b)  Denier  to  ounce  X  0.0036. 

(c)  Dram  to  denier  X  17^. 

(d)  Dram  to  ounce  X  0.0625. 

(e)  Ounce  to  denier  X  277^. 
(/)  Ounce  to  dram  X  16. 

To  convert  the  count  of  raw  silk  into  the  equivalent  for 
spun  silk: 

(a)  Denier  system  into  spun  silk  count  —  5282  -T- deniers  = 
spun  silk  count,  and  5282-7-  spun  silk  count  =  deniers. 

(b)  Dram    system    into    spun    silk   count  — 304.7  -f-  drams 
=  spun  silk  count,  and  304.7    -7-spun  silk  count  =  drams. 

(c)  Ounce   system  into  spun  silk  count— 19.4-7-    ounces  = 
spun  silk  count,  and  19. 4 -7- spun  silk  count  =  ounces. 

The  average  limits  *  within  which  the  sizes  of  various  grades 
of  silks  fluctuate  are: 

Raw  silk 9  to  30  deniers 

Organzine 18  to  34     ' ' ' 

Tram 24  to  60       ' ' 

Wild  silk 100  to  300      '  *' 

The  following  table  shows  the  sizes  of  silk  yarns  in  deniers 
as  compared  with  the  sizes  of  cotton  yarns  (English  system): 

*  During  the  process  of  reeling  the  cocoon  filaments,  the  latter  may,  for  one 
reason  or  another,  run  out  previous  to  starting  another  cocoon;  or  to  make  up 
for  the  cocoons  left  out  during  the  reeling,  the  operator  may  add  extra  cocoons. 
From  such  conditions  it  will  easily  be  understood  that  it  is  practically  impossible 
to  produce  a  thread  of  absolute  uniformity  throughout  the  entire  skein.  Owing 
to  this  variation  in  the  size  of  silk,  in  order  to  obtain  accurately  the  size  of  any 
lot  of  silk  under  consideration,  it  is  necessary  to  take  the  average  of  several  tests 
from  different  parts  of  the  bale.  These  irregularities  in  silk  make  it  necessary  in 
commercial  transactions  to  permit  a  variation  of  two  deniers  in  any  lot  of  silk. 


590 


THE  TEXTILE   FIBRES 


COMPARATIVE  TABLE  OF  COUNTS  OF  COTTON  AND  SILK  YARNS  OF  EQUIVALENT 

SIZE 


Cotton. 

Silk. 

Single. 

Double. 

Yards, 
per  Pound. 

Drams. 

Deniers. 

16-1 

32-2 

13,440 

17.04 

296  .  83 

1  8-  1 

36-2 

15,120 

16.89 

294.22 

20-1 

40-2 

16,800 

I5-24 

265.48 

22-1 

44-2 

18,480 

13-86 

241.44 

24-1 

48-2 

2O,l6o 

12.69 

221    O 

6-1 

52-2 

21,840 

11.72 

204  .  16 

28-1 

56-2 

23,520 

10.88 

189.52 

30-1 

60-2 

25,200 

10.  20 

177.68 

32-1 

64-2 

26,880 

9-52 

165.83 

34-i 

68-2 

28,560 

8.96 

156.08 

36-1 

72-2 

30,240 

8.46 

147-37 

38-1 

76-2 

31,920 

8.02 

139.70 

40-  1 

80-2                   33,6oo 

7.62 

132.75 

42-1 

84-2 

35,280 

7.26 

I  26  .  46 

44-i 

88-2 

36,960 

6.92 

120.54 

46-1 

92-2 

38,640 

6.62 

II5-32 

48-1 

96-2 

40,320 

6.34 

IIO.44 

50-1 

IOO-2 

42,OOO 

6.08 

105.91 

52"1 

IO4-2 

43,680 

5.86 

IO2  .08 

54~i 

108-2 

45,360 

5.64 

98.24 

56-1 

1  1  2-2 

47,040 

5-44 

94.76 

58-1 

116-2 

48,720 

5-25 

91-45 

60-  1 

I2O-2 

50.400 

5-o8 

88.48 

62-1 

124-2 

52,080 

4-92 

85-90 

64-1 

128-2 

53,760 

4.76 

82.91 

66-1 

132-2 

55,440 

4.62 

80.48 

68-1 

136-2 

57,120 

4.48 

78.04 

70-1 

140-2 

58,800 

4-35 

75-77 

72-1 

144-2 

60,480 

4-23 

73-68 

74-1 

148-2 

62,160 

4.12 

71.77 

76-1 

152-2 

63,840 

4.01 

69.85 

78-1 

156-2 

65,520 

3-9i 

68.11 

80-1 

160-2 

67.200 

3-8i 

66.37 

82-1 

164-2 

68,880 

3-72 

64.80 

84-1 

1  68-2 

70,560 

3-63 

63-23 

86-1 

172-2 

72,240 

3-55 

61.84 

88-1 

176-2 

73,920 

3.46 

60.  27 

90-1 

180-2 

75,600 

3-39 

58.95 

92-1 

184-2 

77,280 

3  3i 

57.65 

94-1 

188-2 

78,960 

3-24 

56.44 

96-1 

192-2 

80,640 

3-i8 

55-39 

98-1 

196-2 

82,320 

3-n 

54  17 

100-1 

2OO-2 

84,000 

3-05 

53-13 

IO2-I 

2O4-2 

85,680 

2.90 

52.08 

IO4-I 

208-2 

87,360 

2-93 

51-04 

1  06-  1 

212-2 

89.040 

2.88 

50.  16 

108-1 

216-2 

90,720 

2.82 

49.12 

no-i 

220-2 

92,400 

2.77 

48.25 

1  1  2-1 

224-2 

94,080 

2.72 

47.48 

II4-I 

228-2 

95,76o 

2.67 

46-51 

116-1 

232-2 

97,440 

2.63 

45-8i 

118-1 

236-2 

99,120 

2.58 

44-94 

I  20-1 

240-2 

100,800 

2-54 

44.24 

ANALYSIS  OF   TEXTILE  FABRICS  AND  YARNS         591 


The  size  or  count  of  artificial  silk  is  expressed  in  deniers 
corresponding  to  the  number  of  grams  in  a  length  of  9000 
metres.  This  is  very  close  to  the  Lyons  denier. 

(e)  Linen,  Jute,  etc. — The  count  of  linen  yarn  *  is  based 
on  the  number  of  "  cuts  "  of  300  yards  in  one  pound,  j  The 
following  table  gives  the  counts  of  linen  yarns  by  the  weight 
in  grains  of  300  yards  (or  "  cut  ") : 


i-al 

SIS 
i 

Number  of 
Yarn. 

GO 

"H-c  c 

a  M.§ 
>u  £ 
0^0 

s 

Number  of 
Yarn. 

N 

>  «  % 
o^O 

t*5 

Number  of 
Yarn. 

1-sl 

>g2 

o£o 
i-o 

Number  of 
Yarn. 

i-sj 

^«2 

o^O 
o 

fO 

Number  of 
Yarn. 

ft-d 

SM.S 

>«jrg 

o^O 
<*> 

Number  of 
Yarn.  | 

100 

70.00 

260 

26.92 

420 

16.67 

580 

12.07 

800 

8-75 

1500 

4.67 

no 

63.64 

270 

25-93 

430 

16.28 

590 

11.86 

825 

8.48 

1600 

4-37 

1  20 

58.33 

280 

25.00 

440 

I5-9I 

600 

ii  .67 

850 

8.24 

1700 

4.12 

130 

53-85 

290 

24.14 

450 

I5-56 

610 

11.48! 

875 

8.00 

1800 

3.89 

140 

50.00 

300 

23-33 

46O 

15.22 

620 

n  .  29 

900 

7.78 

1900 

3-68 

150 

46.67 

310 

22.58 

470 

14.89 

630 

ii  .  n 

925 

7-57 

2OOO 

3-50 

1  60 

43-75 

320 

21.87 

480 

14-58 

640 

10.94 

950 

7-37 

2250 

3-n 

170 

41.18 

330 

21  .21 

490 

14.29 

650 

10.77 

975 

7.18 

2500  2.80 

1  80 

38.89 

340 

20-59 

500 

14.00 

660 

10.61 

IOOO 

7.00 

2750 

2-55 

190 

36.84: 

350 

2O.OO 

510 

13-73 

670- 

10.45 

1050 

6.67 

3000 

2-33 

2OO 

35-oo 

360 

19.44 

520 

I3-46 

680 

10.29 

IIOO 

6.36 

3250 

2-15 

210 

33-33 

370 

18.92 

530 

13.21 

690 

10.  14 

1150 

6.09 

35°° 

2.OO 

220 

31.82 

380 

18.42 

540 

12.96 

700 

10.00 

1200 

5-83 

/IOOO 

!-75 

230 

30-43 

390 

17-95 

550 

12.73 

725 

9  66 

I25O 

5-6o 

5000 

i  .40 

240 

29.17 

400 

I7.50 

560 

12.50 

750 

9-33, 

1300 

5-38 

6000 

1.17 

250 

28.00 

410 

17.07 

570 

12.28 

775 

9-03 

1400 

5-oo 

7000 

I.  00 

In  determining  the  count  of  bleached  linen  yarns  a  loss 
for  bleaching  is  allowed,  as  follows:  full  bleach,  20  per  cent; 
three-fourth  bleach,  18  per  cent;  half  bleach,  15  per  cent. 

*  Linen  yarns  are  classified  into  hand-spun  and  machine-spun,  and  are  also 
characterized  as  dry-  or  wet-spun.  Dry-spun  yarns  arc  possessed  of  a  greater 
degree  of  firmness,  though  finer  numbers  can  be  obtained  by  wet-spinning.  Tow 
yarns  are  made  from  the  waste  of  flax  spinning  and  are  readily  distinguished  from 
linen  yarns  by  the  numerous  knots  and  shives  which  are  present.  In  Germany 
dry-spun  yarns  range  from  10  to  30*3,  and  wet-spun  yarn  up  to  8o's.  Yarns  as 
fine  as  200  are  spun  in  Belgium  and  Scotland.  Tow  yarns  are  dry-spun  from 
6  to  20,  and  wet  spun  up  to  35. 

f  The  count  of  linen  yarn  may  also  be  obtained  from  the  formula: 

yards  weighed 


Count : 


0.043  X weight  in  grains 


592  THE  TEXTILE  FIBRES 

Jute  yarns  are  numbered  in  the  same  manner  as  linen  yarns, 
the  basis  also  being  the  number  of  cuts  (or  leas)  of  300  yards 
in  one  pound.  In  Holland  the  count  of  jute  yarns  is  given  by 
the  number  of  hectograms  (0.22  Ib.)  in  a  length  of  150  metres. 

The  count  of  jute  yarns  is  also  based  on  the  weight  in  -  ounds 
per  spindle  of  14,400  yards.  That  is  to  say,  if  14,400  yards 
of  the  yarn  weigh  8  pounds  the  count  is  8. 

Hemp  is  reckoned  on  the  same  basis  as  jute. 

Ramie  yarns  are  numbered  like  chappe  silk  in  Europe,  that 
is  to  say,  the  count  denotes  the  number  of  hanks  of  1000 
meters  weighing  i  kilogram;  hence  a  ramie  yarn  of  32  count 
would  be  equivalent  to  20 's  in  the  cotton  count.  The  same 
method  of  numbering  prevails  in  America. 


BIBLIOGRAPHY   OF  THE    TEXTILE   FIBRES 

Alcan.     Etudes  sur  les  arts  textiles  a  1'Exposition  de  1867. 

-  Traite  complet  de  la  filature  du  coton.     Paris,  1875. 

Allen.     Commercial  Organic  Analysis,  vol.  i  and  vol.  3,  part  3.     Philadel- 
phia, 1898. 
Auer.     Ueber  die  Bastfasern  der  Moraceen.  Oester.  Botan.  Zeitsch.,  1903, 

P-  353- 

—  Annuaire  de  1'industrie  liniere.     Dunbar.     Lille. 

Baine.     History  of  the  Cotton  Manufacture  in  Great  Britain.     London, 

1835- 

Barille.     Etude  sur  les  fibres  textiles.     Strassburg,  1868. 
Becker.     Die  Kunstseide.     Halle,  1912. 
Beech.     Dyeing  of  Cotton  Fabrics,  pp.  1-22.     London,  1901. 

Dyeing  of  Woolen  Fabrics,  pp.  1-14.     London,  1902. 

Beltzer  and  Persoz.     Les  matieres  cellulosiques.     Paris,  1911. 
Bernardin.     Nomenclature  nouvelle  des  550  fibres  textiles.     Gaud,  1872. 
Berthold.     Ueber   die   mikroskop.     Merkmale   der   wichstigen   Pflanzen- 

fasern.     1883. 
Biesiadecky.     Artikel  Haut,  Haare    und  Nagel  in    Strieker's  Handbuch 

der  Lehre  von  den  Geweben.     Leipzig,  1871. 
Bolley.     Beitriige  zur  Theorie  der  Farberei. 
Untersuchung    ueber    die    Yamamayseide.  Polyt.  Zeitschrift,  1869, 

p.  142. 

—  and  Schoch.     Ueber  die  Seiden.     Dingl.  Polyt.  Jour.,  1870,  p.  7  . 
Borain.     La  culture  du  coton.     Brussels,  1875. 

Bottler.     Die  vegetabilischen  Faserstoffe.     Leipzig,  1900. 

Die  animalischen  Faserstoffe.    Leipzig,  1902. 

Bouche  and  Grothe.     Ramie,  Rhea,  China-grass  und  Nesselfaser.     Berlin, 

1884. 
Bowman.     The  Structure  of  the  Wool  Fibre.     London,  1908. 

-  The  Structure  of  the  Cotton  Fibre.    London,  1908. 
Bradbury.     Calculations  in  Yarns  and  Fabrics.     Belfast,  1906. 
Brooks.     Cotton  Manufacturing.     Blackburn,  1888. 

—  Handbook  for  Cotton  Manufacture  Students.     London,  1889. 
Browne.     Trichologia  mammalium.     Philadelphia,  1853. 
Bruckner.     Einiges  iiber  die  neue  Gespinnstpflanze  Ramie.     1870. 

593 


594  THE  TEXTILE   FIBRES 

Burkett.     Cotton.     New  York,  1907. 

Butterworth.     Cotton  and  its  Treatment.     Manchester,  1881. 

Carter.     The  Bleaching,  Dyeing  and  Finishing  of  Flax,  Hemp,  and  Jute. 

London,  1911. 

Charpentier.     Les  textiles;  Ency.  Chimique.     Paris,  1890. 
Cherot.     Etudes  sur  la  culture  du  lin,  1845. 
Christy.     New  Commercial  Plants  and  Drugs.     1882. 
Clark.     Practical  Methods  in  Microscopy.     Boston,  1900. 
Cross  and  Bevan.     Cellulose.     London,  1895. 

-  Researches  on  Cellulose,  1895  to  1900.     London,  1-50  -. 

-  Researches  on  Cellulose,  1900  to  1905.     London,  190! 

-  Researches  on  Cellulose,  1905  to  1910.     London,  1912. 

-  Paper  Making,  pp.  i-no.     London,  1900. 

-  Bevan,  and  King.     Report  on  Indian  Fibres.     London,  1887. 
Crum.     On  the  Cotton  Fibre.     186? . 

Cuniasse  et  Zwilling.     Essais  du  commerce;    Matieres  textiles,  pp.  225-232. 

Paris,  1901. 

Dana.      Cotton  from  Seed  to  Loom.    New  York,  1878. 
Dannerth.     Methods  of  Textile  Chemistry.     New  York,  1908. 
Danzer.     Les  industries  textiles  a  1'Exposition  de  1889.     Paris,  1889. 
Davis,   Dreyfuss,   and   Holland.     Sizing  and   Mildew  in   Cotton   Goods. 

Manchester,  1883. 

Demoor.     Lin,  culture  et  rouissage.     1857. 
Dept.  of  Agriculture.     Yearbook,  1903.     Silk  Culture  Bulletin. 
Deschamps.     Le  coton.     Paris. 
Dickson.     Fibre  Plants  of  India.     1865. 
Dodge.     Descriptive  Catalogue  of  the  Useful  Fibre  Plants  of  the  World. 

Report  No.  9  of  the  U.  S.  Dept.  of  Agriculture,  1897. 

-  Report  on  Flax  Culture.     No.  10,  U.  S.  Dept.  of  Agriculture.     1898. 
Donnell.     History  of  Cotton.     New  York,  1872. 

Dupont.     La  filature  du  coton.     Paris,  1881. 

Duseigneur-Kleber.     Le  cocon  de  soie.     Paris,  1875. 

Eble.     Die  Lehre  von  den  Haaren.     2  vols.     Vienna,  1831. 

Editors   of   the    "Dyer   and    Calico    Printer."     Mercerisation.     London, 

1903. 

Ellison.     Handbuch  der  Baumwollcultur.     Bremen,  1881. 
Engel.     Ueber  das  Wachsen  abgeschnittener  Haare.     1856. 
Erdl.     Vergleichende  Darstellung  des  inneren  Baues  der  Haare.     1841. 
Favier.     Note  industrielle  sur  la  ramie.     Avignon,  1882. 
Fiedler.     Die  Materialien  der  Textil-Industrie.     Hanover,  1909. 
Flatters.     The  Cotton  Plant.     London,  1906. 
Focke.     Mikrosk.  Untersuch.  der  bekannteren  Gespinnstfasern,  der  Shoddy- 

wolle,  etc.     Archiv.  der  Pharmacien,  1886. 


BIBLIOGRAPHY  OF  THE  TEXTILE  FIBRES  595 

Fremy.     La  ramie.     Paris,  1884. 

Frey.     Das  Mikroskop  fur  Aertze,  etc. 

Ganeval.     Le  coton.     Lyons,  1881. 

Ganswindt.     Die  Technologic  der  Appretur.     Vienna,  1907. 

Gardner,  P.     Mercerisation  und  Appretur.     Berlin,  1912. 

Gardner,  W.     Wool  Dyeing,  part  i,  pp.  7-19.     Philadelphia,  1896. 

Geldard.     Handbook  on  Cotton  Manufacture.     New  York,  1867. 

Georgevics.     Chemical  Technology  of  the  Textile  Fibres.     Trans.  Salter. 

London,  1902. 
Gnehm.     Taschenbuch  fiir  die  Farberei  und  Farbenfabriken :   "Gespinnst- 

fasern,"  pp.  1-17.     Berlin,  1902. 
Grothe.     Technologic  der  Gespinnstfasern.     Vollstandiges  Handbuch  der 

Spinnerei.     Berlin,  1876  and  1882. 
—  "Textil  Industrie"  in  Muspratt's  Chemie,  vol.  5. 
Gurlt.     Yergleichende  Untersuchungen  ueber  die  Haut.     Berlin,  1844. 
Halphen.     La    pratique  des  essais  commerciaux  et  industriels,  matieres 

organiques;   Textiles  et  tissues,  pp.  326-342.     Paris,  1893. 
Hamon.     Culture  du  lin  en  Bretagne. 
Hanausek  und  Nebeski.     Mikroskopie  von  Pelzhaaren.     Jahresbericht  der 

Wiener  Handelsakademie.     1884. 

Hannan.     Textile  Fibres  of  Commerce.     London,  1902. 
Heermann.     Dyers'    Materials:     "Textile    Fibres,"    pp.    16-24.     Trans. 

Wright.     London,  1900. 

—  Untersuchungsmethoden  der  Textil-chemie.     Berlin,  1902. 

Mechanisch-und  Physikalisch-technische  Textiluntersuchungen.  Ber- 
lin, 1912. 

Herzfeld.     Das  Farben  und  Bleichen,  etc.     Berlin,  1890. 

Herzinger.     Die  Technik  der  Mercerisation.     Reuss,  1911. 

Herzog.  Die  Unterscheidung  der  natiirlichen  und  kunstlichen  Seiden. 
Dresden,  1910. 

—  Mikrophotographischer   Atlas   der   technisch   wichtigen   Faserstoffe. 

Munich,  1908. 

Higgins.  On  the  Microscopic  Character  of  Cotton.  Proc.  Lit.  and  Phil. 
Soc.  of  Liverpool,  1872. 

Hofmann.     Traite  pratique  de  la  fabrication  du  papier.     1876. 

Hohnel.  Die  Mikroskopie  der  technisch  verwendeten  Faserstoffe.  Leip- 
zig, 1887. 

—  Die    Unterscheidung   der   pflanzlicheri    Textilfasern.     Dingl.    Polyt. 

Jour.,  vol.  246,  p.  465. 

— •- -Ueber  pflanzliche  Faserstoffe.     Yienna,  1884. 
-  Ueber  den  Bau  und  die  Abstammung  der  Tillandsiafaser.     Dingl. 

Polyt.  Jour.,  vol.  234,  p.  407. 
—  Beitrage  zur  technischen  Rohstofflehre,     Dingl.  Ployt.  Jour.,  vol.252. 


596  THE  TEXTILE  FIBRES 

Hoyer.     Das  Papier,  seine  Beschaffenheit  und  deren  Priifung.     Munich, 

1881. 

Hiibner.     Bleaching  and  Dyeing  of  Vegetable  Fibrous  Substances.     Lon- 
don, 1912. 

Hiilse.     Die  Technik  der  Baumwollspinnerei.     Stuttgart,  1863. 
Hummel.     Dyeing  of  the  Textile  Fibres.     London,  1896. 
Hyde.     The  Science  of  Cotton  Spinning.     Manchester. 
Janke.     Wool  Production.     1864. 

Joclet      Chemische  Bearbeitung  der  Schafwolle.     Leipzig,  1902. 
Karmarsh.     Technisches  Worterbuch.     Artikel  "Baumwolle"  und  "Ge- 

spinnstfasern."     1876. 

Kerebel.     De  Fexamen  des  fibres  textiles  vegetales  dans  la  marine,  1890. 
Knecht,  Rawson,  and  Loewenthal.     Manual  of  Dyeing.     London,  1910. 
Kolliker.     Handbuch  der  Gewebelehre. 
Kuhn.     Die  Baumwolle.     Leipzig,  1892. 
Lacroix.     Grand  dictionnaire  industriel.     Paris,  1888. 
Lafar.     Technical  Mycology,  vol.  i.    London,  1898. 
de  Lasteyrie.     Du  cotonnier  et  de  sa  culture.     Paris,  1808. 
Le  Blanc.     Systeme  complet  de  la  filature  du  coton.     Paris,  1828. 
Lecomte.     Textiles  vegetaux.     Paris. 

—  La  ramie.     (Rev.  gen.  sciences.)     Paris,  1890. 
Lee.     The  Vegetable  Lamb  of  Tartary.     London,  1887. 
Leigh.     The  Science  of  Modern  Cotton  Spinning.     Manchester,  1877. 
Leydig.     Lehrbuch  der  Histologie. 
L'Homme.    Laine  et  coton.     Paris,  1881. 

Lobner,  H.     Studien  und  Forschungen  iiber  Wolle.     Grunberg,  1898. 
Lobner,  O.     Carbonisation  der  Wolle.     Grunberg,  1891. 
Lunge.     Chemische  technische  Untersuchungsmethoden,  vol.  3,  pp.  1026- 

1056.     Berlin,  1900. 

Lyman.     Cotton  Culture.     New  York,  1868. 
Mallet.     Cotton:   the  Chemical,  etc.,  Conditions  of  its  Culture.     London, 

1862. 

Marcandier.     Traite  du  chanvre.     Paris,  1795. 
Marsden.     Cotton  Spinning.     London.  1888. 
Massot.    Appretur  und  Schlichte- Analyse.     Berlin,  1911. 
Masters.     On  a  New  Species  of  Gossypium.     Jour.  Linn.  Soc.,  London, 

1882. 
Mitchell  and  Prideaux.     Fibres  Used  in  Textile  and  Allied  Industries. 

London,  1910. 
Molisch.     Neue  Methode  zur  Untersuchung  der  Thierfasern  und  Pflanzen- 

fasern.    Dingl.  Polyt.  Jour.,  vol.  261,  p.  135. 
Moller.    Waarenkunde.     Vienna,  1879. 
Monie.    The  Cotton  Fibre.     Manchester,  1890. 


BIBLIOGRAPHY  OF  THE  TEXTILE  FIBRES  597 

Miiller.     Anleitung    zur    Ausfiihrung    textil-chemischer    Untersuchungen. 

Vienna,  1904. 
Nathusius-Konigsborn.     Das  Wollhaar  des  Schafes  in  histologischen  und 

technischen  Beziehung.     Berlin,  1866. 
Niess.     Die  Baumwollspinnerei.     Weimar,  1885. 
Oesterreichs.  Wollen-  und  Leinenindustrie. 

Oger.     Traite  elementaire  de  la  filature  du  coton.     Miilhausen,  1839. 
O'Neill.     A  Dictionary  of  Calico  Printing  and  Dyeing.     London,  1862. 

—  Experiments  and  Observations  on  Cotton.     London,  1865. 

—  On  an  Apparatus  for  Measuring  Tensile  Strength  of  Fibres.     London, 

1865. 

Oppel.     Die  Baumwolle.     Leipzig,  1902. 
Orschatz.     Ueber   den    Bau    der   wichtigsten    verwendbaren    Faserstoffe. 

Polyt.  Centralblatt,  p.  1279.     1848. 

Parent-Duchatelet.     Le  rouissage  du  cnanvre.     Paris,  1832. 
Parlatore.     Le  specie  dei  cotoni.     Florence,  1866. 

Pelouze.     Expose  complet  de  la  culture  du  coton  aux  Antilles.     Paris,  1838. 
Persoz.     Essai  sur  le  conditionnement  de  la  soie,  etc.     Paris,  1878. 

—  Le  conditionnement  de  la  soie.     Paris,  1887. 
Pfuhl.     Papierstoffgarne.     Riga,  1904. 

Polleyn.     Dressings  and   Finishings  for  Textile  Fabrics.     Trans.  Salter. 

London,  1911. 
Quatremere-Disjonval.     Essais  sur  les  caracteres  qui  distinguent  les  cotons 

de  diverses  parties  du  monde.     Paris,  1  784. 
Rawson,   Gardner,  and  Laycock.   -Dictionary  of  Dyes,   Mordants,  etc.; 

articles  relating  to  Textile  Fibres.     London,  1901. 
Reiser  and  Spennrath.     Handbuch  der  Weberei.     Berlin,  1885. 
Reissek.     Die  Fasergewebe  des  Leins,  etc.     Vienna,  1852. 
Renouard.     Les  arts  textiles. 

—  Les  fibres  textiles  des  pays  tropicaux. 
Reybaud.     Le  coton.     Paris,  1863. 

Richard.     Die  Gewinnung  der  Gespinnstfasern.      Brunswick,  1881. 
Rohde.     Beitrage  zur  Kenntniss  des  Wollhaares.    Eldenaer  Archiv.     1856, 


Romen.     Die  Bleicherei,  Farberei  und  Appretur  der  Baumwollwaren,  etc. 

Berlin,  1879. 
Royle.     On  the  Culture  of  Cotton  in  India,  etc.     London,  1851. 

-  The  Fibrous  Plants  of  India.     London,  1855. 

Sadtler.     Handbook  of  Industrial  Organic  Chemistry.     Philadelphia,  1897. 
Saladin.     La  filature  du  coton.     Paris. 
Sansone.     Dyeing  Wool,  Silk,  Cotton,  etc.,  vol.  i,  pp.  18-32,  London,  1888. 

—  Printing  of  Cotton  Fabrics,  pp.  53-73.     London,  1901. 
Savorgnan.     Coltivazione  ed  industria  delle  piante  tessili.     Milan,  1890. 


598  THE  TEXTILE  FIBRES 

Schacht.     Die  Prufung  der  im  Handel  vorkommenden  Gewebe.     Berlin, 

1853- 

Schick.     Der  Textilchemiker.     Reuss   1910. 
Schlesinger.     Examen  microscopique  et  microchemique  des  fibres  textiles. 

Paris,  1875. 

Schmidt.     Schafzucht  und  Wollkunde.     1852. 
Schunck.     On  Some  Constituents  of  the  Cotton  Fibre.     London,  1868. 

-  On  the  Color  of  Nanking  Cotton.     London,  1873. 
Shepperson.     Cotton  Facts.     New  York. 

Sicard.     Guide  pratique  de  la  culture  du  coton.     Paris,  1866. 

Siegfried.     Sur  le  coton  de  1'Algerie. 

Silberbach.     Handbook  of  Vegetable  and  Mineral  Products.     Liverpool, 

1887. 

Silbermann.     Die  Seide.     2  vols.     Dresden,  1897. 
Squier.     Tropical  Fibres.     New  York,  1863. 
Silvern.     Die  kiinstliche  Seide.     Berlin,  1912. 
Terwagne.     Du  lin,  du  chanvre,  etc.     Lille,  1852. 
Thomson.     The  Sizing  of  Cotton  Goods.     Manchester,  1875. 
Thorpe.     Dictionary  of  Applied  Chemistry:    articles  relating  to  Textile 

Fibres.     New  York,  1895. 

Todaro.     Relazioni  sulla  cultura  dei  cotoni  in  Italia.     Rome,  1878. 
Trotman   and   Thorpe.     The   Principles   of  Bleaching  and   Finishing  of 

Cotton.     London,  1911. 
United  States  Report.     The  Cotton  Plant.     Bulletin  No.  33,  Dept.  of 

Agriculture,  1896. 
Ure.     The  Philosophy  of  Manufacture.    London,  1835. 

—  On  the  Cotton  Manufacture  of  Great  Britain.     London,  1861. 

-  Cotton  Spinning  and  Manufacture.     London,  1861. 
Vautier.     L'art  de  la  filature  du  coton.     Paris,  1821. 
Vetillart.     Etudes  sur  les  fibres  vegetales  textiles.     Paris,  1876. 
Vignon.     La  soie.     Paris,  1890. 

Wagner.     Handbuch  der  Physiologic.     Artikel  "Der  Haut." 

-Chemical    Technology:     "Fibres,"    pp.    798-871.  '  Trgps.    Crookes. 

New  York,  1897. 

Walmsley.     Cotton  Spinning.     London,  1883. 
Walton.     The  Story  of  Textiles.     Boston,  1912. 
Watson.     Fibre-yielding  Plants  of  India.     1870. 
Watto.     Cotton.     London,  1877. 
Weddel.     Monographic  des  Urticees.     Paris,  1866. 

Weisner.     Die  Rohstoffe  des  Pflanzenreiches,  vol.  2,  "Fasern."    Leipzig, 
1903. 

—  Beitrage  zur  Kenntniss  der  indischen  Faserpflanzen.     1870. 

—  Einleitung  in  die  technische  Mikroskopie.     1867. 


ANALYSIS  OF  THE  TEXTILE  FIBRES  599 

Weisner  und  Prasch.  Ueber  die  Seiden,  in  Mikroskop.  Untersuchungen, 
1872,  p.  45;  und  Dingl.  Polyt.  Jour.,  p.  190.  1868. 

Wertheim.     Ueber  den  Bau  des  Haarbalges.     Vienna,  1864. 

Wheeler.     A  Handbook  of  Cotton  Cultivation  in  Madras.     Madras,  1862. 

Willems.     La  soie  artificielle.     Paris. 

Witt.  Chemische  Technologic  der  Gespinnstfasern,  part  i.  Brunswick, 
1891.  Part  n,  1911. 

Worden.    Nitrocellulose  Industry.     2  vols.    New  York,  1911. 

Zetzsche.     Faserstoffe.    Leipzig,  1905. 

Zipser.     Textile  Raw  Materials.     (Trans.  Salter.)    London,  1901. 


INDEX 


A 

PAGE 

Abaca 435 

Abelmoschus  tetraphyllos 156 

Absorbent  cotton 258 

Abutilon,  varieties  of 399 

Abutilon  aviccnnae 399 

incanum 399 

Acetate  silk 62 

Acid  index  of  bleached  cotton 515 

Acidified  wool,  dyeing  properties  of 62 

Acid-proof  fabrics 290 

Adamkiewitz's  test 137 

Adenos  cotton 221 

Adipocelluloses 282 

Adsorption  theory  in  dyeing 304 

African  bowstring  hemp 452 

cottons 220 

sheep ! 16 

Agave  americana 157 

fibre 439 

Algodon  de  seda 350 

Alkali-cellulose 278,  309 

Allanseed  cotton 211 

Aloe  fibre 443 

hemp 507,  509 

Aloe  pcrfoliata 156 

Alpaca 98 

Ambari  hemp.  .  . 416,  429 

action  of  steam  on 430 

American  cotton 211 

Amiantus  asbestos 10 

Amino-cellulose 296 

Amyloid • 276 

Analysis  of  textile  fabrics  and  yarns 517 

textile  fibres 461 

Analytical  table  for  mixed  fibres 482 

[601 


602  INDEX 

PAGE 

Anaphe  silk 1 18 

Angola  sheep 16 

Anilin  sulphate,  reactions  with 1 79 

Animal  and  vegetable  fibres,  distinction  between 6,  466 

Animal  fibres 6 

hair,  structure  of 14 

Animalized  cotton 381 

Annual  silkworms 107 

Anthercaa  assama 1 18 

mylitta 118 

pernyi 1 18,  492 

yama-mai ........ 1 18 

Antiphlogin ,„..,.. 353 

Argali , 16 

Arkansas  cotton 211 

Arryndia  ricini 492 

Arsenic  in  wool 52 

Artificial  fibres,  classes  of 1 1 

horse-hair 286,  373 

lace 373 

rnaline 373 

Artificial  silk,  action  of  water  on 373 

bleaching  of 375 

comparison  of  different  varieties  of 377 

covering  power  of 374 

density  of , . 376 

drying  of 375 

dyeing  properties  of .  , 375 

hygroscopic  properties  of 376 

lustre  of 376 

properties  of 373 

scrooping  of 375 

size  of 374 

statistics  for 351 

strength  of 372 

tensile  strength  of 375 

varieties  of 351 

silks '. 13 

identification  of 483 

microscopical  comparison  of -<T 489 

testing  with  ruthenium  red 488 

Artificial  silk  yarns,  numbering  of A 591 

wool 79,  407 

Asbestos ._ . ,       9 

dyeing  of 1 1 

fabrics  from 1 1 

method  of  spinning 1 1 


INDEX  603 


Asdepias  cornuti 500 

cotton 347 

Ash,  determination  of  in  vegetable  fibres 181 

in  textile  fabrics,  analysis  of 571 

Ashmouni  cotton 218 

Attacus  atlas 118 

lunula 492 

ricini 1 18 

Attalea  fttnifera ,., 1 74,  458 

Auchenia  huanaco , 95 

llama .. .. , 95 

paco ... ...... 92 

vicuna , 94 


Baden  hemp ....... 419 

Bahmia  cotton ....... 217 

Bakrabadi  jute 402 

Banana  fibre 157 

Barbadoes  cotton 208 

Barwall  sheep 16 

Bash  hemp 418 

Basinetto  silk 113 

Basketry  fibres , , 163 

Bast  fibres 152,  154,  165,  170 

classification  of 171 

reactions  for ,.,,,., 478 

Bastose ..,.,,,,,.,. . , ,....- 404 

Bauhinia  raccmosa .,.,. 156,  174 

Bave  of  silk  fibre i  t «»«%»»».«»%%  v*  v« I T4 

Bayko  yarn , , 12 

Bearded  sheep . . 16 

Beard-hair 17 

Beaumontia  grandi flora 349 

Benders  cotton 211 

Bengal  hemp 416 

Bhatial  jute 402 

Bibliography  of  textile  fibres 593 

Big-horn  sheep 16 

Biuret  test „ 137 

Black-faced  sheep 16 

Black-fellow's  hemp 416 

Black  wool  in  sheep , 52 

Bleached  cotton,  acid  index  of 515 

analysis  of 512 


604  INDEX 

PAGE 

Bleached  cotton,  copper  index  of 515 

test  for  oxycellulose  in 515 

Bleaching  wool  with  peroxides 68 

with  potassium  permanganate. 68 

Blue  bender  cotton 264 

Boehmeria  nivea 156,  410 

tenacissima 156,  410 

Boiled-off  liquor 131 

Bombax  carolinum 344 

ceiba 343,  501 

cotton 343,  510 

cumanensis 344 

heptaphyllum 1 56,  343,  501 

malabaricum 344 

pentandrum 345 

pubescens 344 

rhodognaphalon 344 

villosum .   344 

Bombay  hemp 416 

Bombyx  mori ; 106 

Bourette  silk 1 29 

Boweds  cotton 211 

Bowstring  hemp 416 

Bradford  method  of  sorting  wool 19 

Brazilian  sheep 16 

Brightening  of  silk 125 

Brin  of  silk  fibre 114 

Broad-tail  sheep .- 16 

Bromdia  argentina 457 

fibres ....   455 

karatas 156 

pinguin .    157,  456 

sylvestris 457 

Broom-grass 157 

Brown  Egyptian  cotton 2  20 

hemp 416 

Brush  fibres 162 

Byssus  silk 150 


C 

Caesar  weed  fibre 452 

Cago  she.ep 16 

Calcino  in  silkworm ". 115 

Calculations  in  conditioning  textiles 539 

Calcutta  hemp 402 


INDEX  605 

PAGE 

Calf  hair 101 

Calotropis  giganlca 156,  348,  501 

procera 500,  510 

Camel  hair 96,  98 

noils 98 

Canadian  asbestos i  r 

Canapa  piccolo 417 

Cannabis  saliva .  .  .  . , 156,  41 7 

Caraguala  fibre 457 

Carbohydrates 268 

Carbonization  of  shoddy 80 

Carbonizing  rags 277 

Carded  silk ." 1 20 

yarns 46 

Carludovica  Palmala 162 

Caryota  urens : 162,  458 

Cashmere 88 

Cat-hair 102 

Caulking  fibres 163 

Caustic  soda,  recovery  of  in  mercerizing 332 

Cebu  hemp 416 

Ceiba  cotton 343,  502 

Cellulo  silk 363 

Celluloid 290 

Cellulose 260,  268 

constitution  of 271 

critical  temperature  for 300 

degree  of  hydration  of 312 

determination  of  in  vegetable  fibres .    182 

mucilage  value  of 300 

Cellulose  acetate 280 

<    aceto-sulphate 281 

benzoate 280 

hexanitrate , ....... 29 1 

hydrate 309,  339 

nitrates 292 

pentanitrate 292 

peroxide -.  . . .   301 

sulphate .' 281 

thiocarbonate 278 

xanthate .   278 

Century  plant 444 

Chapped  silk 1 28 

Chardonnet  silk 353 

Chemical  analysis  of  textile  materials 528 

Chemical  reactions  of  principal  fibres 463 

China  grass „ 410,  503 


606  INDEX 

PAGE 

Chinese  jute 399 

sheep ,.,.,.,.,...... 16 

Chlorinated  wool 69 

detection  of , ,  ,V, 69 

Chlorinating  wool,  method  of 69,  70 

Cholesterol ,.,-..... 50 

Chrysotile 10 

Cibotium  glaucum .  ,  , , . . . , , 346 

Classes  of  fibres 5 

Classification  of  textile  fibres i 

wool  fibres  in  fleece . '. 17 

Cochlospermum  gossypium 502,  510 

Cocoon,  the  silk 1 1 1 

Cocos  nucifera , 157 

Cocuiza  fibre 425 

Cohesiveness  of  textile  fibres 4 

Coir , 509 

fibre 156,  447 

Collodion 290 

silk 353 

Colloidal  nature  of  fibres 6 

Colorado  River  hemp 416 

Combed  yarns 45 

Commercial  vegetable  fibres 461 

Common  hemp 417 

sheep 16 

Compound  celluloses 281 

Condenser  yarns , 210 

Conditioned  weight,  table  showing 549 

Conditioning,  calculations  involved  in. 539 

Conditioning  apparatus 537 

at  Bradford 534 

of  textiles 532 

of  wool 76 

Congo  sheep 16 

Copper  index  of  bleached  cotton 515 

Corchorus  capsularis 156,  399 

decemangulatus 399 

fuscus 399 

olitorious 1 56,  399 

Cordage  fibres 161 

strength  of 427 

Cordia  latiiolia 156 

Cordonnet  silk 130 

Cork  tissue 175 

Corypha  timbraculifera 157 

Cosmos  fibre 80 


INDEX  607 

PAGE 

Cotted  fleeces 50 

Cotton & ;' . . . . ". , . 503,  509 

absorbent 258 

action  of  acids  on 285 

action  of  alkalies  on ^ 295 

action  of  ammonia  on 296 

action  of  coloring  matters  on 304 

action  of  concentrated  caustic  soda  on 297 

action  of  cuprammonium  solution  on 284 

action  of  ferments  on 306 

action  of  heat  on 282 

action  of  human  saliva  on 306 

action  of  hydrofluoric  acid  on 292 

action  of  magnesium  chloride  on 303 

action  of  metallic  salts  on 302 

action  of  mildew  on 306 

action  of  nitric  acid  on 289 

action  of  organic  acids  on 292 

action  of  oxalic  acid  on 293 

action  of  sodium  sulphide  on 297 

action  of  sulphur  on 297 

action  of  tannins  on 294 

action  of  water  on 284 

action  of  zinc  chloride  on 285 

albuminous  matter  in 267 

boiling-out  of.  .  .... 261 

botany  of 188 

chemical  constitution  of 260 

chemical  reactions  of 282 

coloring  matter  in 264 

degree  of  hydration  of 340 

degree  of  mercerization  of 338 

derivation  of  word 186 

effect  of  kier-boiling  on 295, 

electrical  potential  of 73 

first  cultivation  of  in  U.  S 187 

foreign  names  for 205 

grading  of  in  America 224 

grading  of  in  Europe 214 

history  of 184 

hygroscopic  quality  of 255 

impurities  in  raw 260 

manufactured  value  of  one  pound  of 241 

mineral  matter  in 264 

origin  and  growth  of 188 

products  of  dry  distillation  of 283 

regain  for 257 


608  INDEX 

PAGE 

Cotton,  statistics  of 188 

tendering  of  with  sulphur  dyes 287 

varieties  of 205 

Cotton  and  linen,  distinction  between 473 

Cotton  cloth,  analysis  of 570 

mercerizing  of t 331 

Cotton  fabrics,  flameproofing  of 303 

Cotton  fibre,  action  of  Schweitzer's  reagent  on 242 

anatomical  structure  of 241 

changes  due  to  mercerizing 312 

chemical  analysis  of 262 

conditions  affecting  quality  of 204 

dimensions  of 229 

method  of  analysing 263 

microchemical  reactions  of 249 

microscopy  of 245 

number  of  twists  in 227 

physical  structure  of 227 

physiological  development  of 200 

primary  elements  of 204 

spinning  qualities  of 250 

structural  parts  of 242 

tensile  strength  of 250 

Cotton  grass 168,  496 

Cotton  plant,  analysis  of 198 

botanical  classification  of 213 

cross  fertilization  of 213 

description  of 189 

fertilizing  constituents  in « 199 

method  of  cultivation  of 191 

Cottonseed,  analysis  of 199 

products  obtained  from 198 

utilization  of 198 

Cotton  sliver,  mercerizing  of 330 

Cotton  tree 212,  343 

Cotton  warps,  mercerizing  of 330 

Cotton-wax 261 

Cotton  wool,  dimensions  of  fibre  of 156 

Cotton  yarn,  contraction  of  during  mercerizing 323 

count  of 215 

determining  count  of 579 

Cottonized  flax 390 

ramie 412 

Count  of  woolen  yarn  3 582 

Count  of  yarn,  definit'on  of 577 

variations  allowable  in 580 

Courtrai  flax 386 


INDEX  609 

PAGE 

Cow  hair 99 

Crepon  effects,  on  union  goods 66 

on  woolen  goods 72 

Cretan  hemp 416 

sheep '. 16 

Crimean  sheep 16 

Crin  vegetal 160 

Oinol p|| 373 

Crololaria  juncca 156 

Cuba  bast 161 

Cuban  hemp 416,  424 

Cuprammonium  hydrate,  preparation  of 269 

silk 360 

Cuprate  silk , 352 

Curumbar  sheep * 16 

Cutose 175,  282 

Cyperus  unilans 163 

Cyprian  gold  thread.  ,,,,,,, 12 


D 

Dacca  cotton . 224 

Date  palm  fibre 157 

Dead  cotton ^. 228 

Deccan  sheep 16 

Degumming  silk 131 

Denier,  definition  of 583 

different  forms  of 583 

Deo  cotton 207 

Deora  jute 402 

Desi  jute 401 

Deswal  jute 401 

Diazotized  wool 64 

Dicotyledonous  plants 152 

Discharging  silk 131 

Doe,  beard-hair  of 31 

Domestic  sheep : 17 

Double  cocoons 113 

Dukhun  sheep 16 

Du  Vivier's  silk 360 

Drying  of  wool 76 

Durability  of  fibres ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,.  f ,,,,,,,,,,,,,,,,  5 


610  INDEX 


E 

PAGE 

Echappe  silk 129 

Economic  classification  of  vegetable  fibres 160 

Economic  limit  of  length  of  fibres v  2 

Edredon  vegetate 346 

Egyptian  cotton,  varieties  of 218 

Elairerin 51 

Elais  gmneensis 157 

Electrical  potential  of  fibres 73 

Elephant  grass 168 

Embroidery  silk 130 

Endochrome  in  cotton  fibre 203 

Equivalent  counts  of  yarns 578 

Eriodendron  anfracttwsum 345,  501 

Escurial  sheep 23 

Esparto 505 

fibre 157 

grass 156 

Excelsior  fibre 159 

Extract  wool .,,,,,,,,,,,,, 79,  80 


F 

Fabric  fibres 160 

False  hemp 416 

False  sisal  hemp v. 416 

Feather-grass  fibre 157 

Fehling's  solution,  preparation  and  use  of 552 

Fezzan  sheep 16 

Fibres  chiefly  used  for  textiles i 

Fibroin 131,  133 

action  of  polarized  light  on  solution  of 140 

analysis  of 134 

chemical  reactions  of 138 

composition  of ...  137 

dipeptide  of 138 

formula  for 134 

of  tussah  silk 14? 

preparation  of  pure 134 

proportion  of  in  raw  silk 135 

saponification  of 134 

Fibro-vascular  bundles 7 

Fiji  sea-island  cotton '. .  217 

Finishing  materials,  estimation  of  on  fabrics 57° 

Pique  fibre 425 


INDEX  611 

PAGE 

Fireproofing  of  cotton  fabrics ; 303 

Flacherie  in  silkworm 115 

Flame-proofing  of  cotton  fabrics 303 

Flax,  grading  of 383 

retting  of 385 

Flax  dust,  composition  of 397 

Flax  fibre,  action  of  steam  on 394 

analysis  of 395 

cell  dimensions  of 394 

chemical  properties  of 392 

color  of 393 

comparison  of  with  cotton 394 

description  of 390 

Flax  in  United  States 383 

Flax  plant,  description  of 383 

Fleece,  qualities  of  fibre  in 22 

Florette  silk 1 29 

Florida  bowstring  hemp .  . 452 

sea-island  cotton 216 

Floss  silk 113,127 

Formic  acid,  use  of  in  mordanting > 71 

Frisons 113 

Frisonnets  silk 113 

Fruit-fibres 153,  166 

Fur,  use  of  in  textiles 15 


G 

Galettame  silk 113 

Galgal  fibre 346 

Gallini  Egyptian  cotton 2i> 

Gambo  hemp 157,  429,  506,  510 

Garar  sheep 16 

Gattine  in  silkworm 115 

Gelatin  silk 372 

Georgia  cotton 211 

Giant  hemp 416 

Ginning 197 

Glass  wool 12 

Glovers'  wool 42 

Goat-hair 88 

Goitred  sheep 16 

Gorilla  yarn 91 

Gossypium  acuminatum 156 

album 205 

arboreum 156,  205,  223 


612  INDEX 

PAGE 

Gossypium  arboreum,  botany  of 211 

barbadense 156,  205 

botany  of 207 

braziliense 205 

chinense 205 

conglomeratum , 156 

croceum 206 

eglandulosum 206 

datum 206 

fructescens 206 

fuscum 206 

glabrum 206 

glandulosum 206 

herbaceum 156,  201 ,217 

botany  of 208 

hirsutum •  • 206,  210,  221 

indicum ' 206 

jamaicense 206 

javanicum 206 

kirkii 206 

latifolium , 206 

leonivum 206 

macedonicum ........ 206 

maritimum •. .-.••• 206 

micranthum 206 

molle 206 

nanking 206 

neglectum > * 206 

nigrum 206 

obtusifolium 206 

oligospermum 206 

paniculatum 206 

perenne 206 

peruvianum 207,  212 

punctatum 207 

racemosum 207 

religiosum 207 

roxburghianum 207 

sandwichense 213 

siamense » 207 

sinense 207 

stocksii . , 207 

strictum .  . 207 

tahUense •  •  •  • 212 

tomentosum 207 

tricuspidatwn •  207 

vilifolium 207 


INDEX  613 

PAGE 

Oossypium  wightiamim 207 

Grading  of  cotton 224 

Grass  cloth 412 

Grasserie  in  silkworm 116 

Green  ramie 410 

Grege  silk 127 

Guimara  fabric 435 

Guinea  sheep 16 


H 

Hair  fibres 168 

follicle 26 

Hayti  hemp 416 

Heat-retaining  value  of  fabrics 8 

Hemp : 157,  416,  504,  512 

action  of  steam  on 394 

varieties  of 416 

Hemp  and  flax,  distinction  between 421 

Hemp  fibre,  microscopy  of 418 

retting  of 418 

Hemp  yarns,  numbering  of 592 

Hibiscus  cannabinus 156 

datus 161 

esctilenttis 429 

Hingunghat  cotton 220 

Holoptelia  integrifolia 156 

Honduras  silk-grass 457 

Hooniah  sheep 16 

Hop  fibre 157 

Hornblende , 9 

Horse-hair 101 

Hoya  viridiflora 501 

Humulus  lupulus 157 

Hydrocellulose 276,  288,  339 

Hydrolysis  of  vegetable  fibres 181 

Hygienic  flannels 350 

Hygroscopic  moisture  in  fibres,  method  of  determining 259 


I 

Ife  hemp 416,  452 

Indian  cotton,  varieties  of 221 

hemp 417 

lodm-sulphuric  acid  reagent,  reactions  with 177,  474 


614  INDEX 

PAGE 

Isocholesterol 51 

Istle  fibre 450 

Ita  palm  fibre 157 

Italian  hemp,  analysis  of 423 

silk,  analysis  of 132 

Ixtle  fibre 445 


J 

Jangipuri  jute 402 

Japanese  braid  fibres 162 

floor  mattings 163 

raw  silk,  analysis  of 132 

Jaumave  istle 450 

Javanese  sheep 16 

Jubbulpore  hemp 417 

Juncus  effusus 163 

Jute  ..  .   399,  505,  5ii 

action  of  steam  on 394 

analysis  of 405 

•  chemical  composition  of 404 

commercial  varieties  of 401 

distinction  from  other  fibres 477 

retting  of 400 

Jute  butts 401 

cuttings 401 

fibre x. i57 

microscopy  of 4°2 

physical  properties  of 406 

Jute  yarns,  numbering  of 59 l 


K 

Kapok 345 

analysis  of 346,  481 

detection  of  cotton  in 481 

Karatas  plumieri 457 

Karimganji  jute 402 

Kemps 42 

Keratin 53 

Kidney  cottons 205,  223 

Kittool  fibre -.-..- i°2 

Kittul  fibre 162,  459 

Kjeldahl's  process  of  analyzing  weighted  silk 56° 

Kosmos  fibre 4°7 


INDEX  615 

PAGE 

Kumbi  fibre 346 

Knri-wala  silk,  analysis  of , 132 

Kydia  calycina 156 


L 

Lace-barks , 161 

Lace-bark  fibre 157,161 

Lactic  acid,  use  of  in  mordanting 71 

Lagetta  lintearia 157 

Lana  del  tambor 344 

Lana  vegetal- 344 

Lanuginic  acid 55 

reactions  of 56 

Lasiosyphon  speciosus 156 

Lea,  definition  of 579 

Leaf-fibres 153,  165 

Leaf-hairs 152 

Lechuguilla  fibre 445 

Lehner's  silk 359 

Licella  yarn 460 

Ligneous  matter,  chemical  reactions  for 478 

Lignification,  chemical  constants  of 410 

Lignin ; 175,  177 

amount  in  textile  fibres 180 

detection  of  in  fibres 1 79 

test  for 155 

Lignocellulose 175,  282,  407 

action  of  chlorin  on 408 

phloro  glucinol  test  for 409 

Lignocellulose  and  cellulose,  distinction  between 408 

Linden  bast 156,  157 

Linen 157,  382,  503,  510 

action  of  Schweitzer's  reagent  on 392 

ash  in 395 

chemical  properties  of 392 

color  of 393 

hygroscopic  nature  of 397 

lustre  of 393 

microchemical  reactions  of 394 

microscopy  of 390 

regain  in  conditioning 397 

Linen  and  cotton,  chemical  distinction  between 394,  473 

Linen  and  hemp,  distinction  between 394,  477 

Linen  and  tow  yarns,  distinction  between 393 

Linen  wax , , 396 


616  INDEX 

PAGE 

Linen  yarns,  loss  in  bleaching 393 

numbering  of 398,  59 1 

spinning  of 398 

Linkmeyer's  process  for  artificial  silk 363 

Linters 199 

Linum  angustifolium 382 

catharticum 382 

crepitans 382 

lewisii 382 

Perenne 382 

usitatissimum 1 56,  382 

Llama 91 

fibre 95 

Louisiana  cotton 211 

Lumen,  in  plant  fibres 154 

Lustering  of  silk 125 

Lustra-cellulose 352 

Lustre  of  fibres 5 

Lustre  of  wool,  effect  of  chemical  agents  on , 36 

Lygaum  spartum 157 

Lyon's  gold  thread 12 


M 

Maceo  cotton 223 

Madagascar  sheep 16 

Majagua  fibre .v 429 

Manila  hemp 435.  5°7,  5°8,  51° 

action  of  steam  on 394 

Manila  hemp  and  sisal,  distinction  between 478 

fire 157 

Many-horned  sheep 16 

Marabout  silk 129 

Maranhams  cotton 223 

Marine  fibre 434 

Matting  fibres 163 

Mauritia  fiexuosa 157 

Mauritius  hemp 443 

Median  layer  in  fibres 1 70 

Meliotus  alba 157 

Memphis  cotton 211 

Mercerized  cotton - 3°8 

boiling-out  of  cotton  for 331 

cause  of  lustre  in 313 

distinction  of  from  ordinary  cotton .  . ' 337 

dyeing  properties  of -..-., 335 


INDEX  617 

PAGE 

Mercerized  cotton  increased  affinity  of  for  dyes 334 

iron  in 266 

microscopy  of . 341 

physical  appearance  of 312 

properties  of 333 

reactions  of 336 

scroop  in 327 

tests  for 338 

Mercerized  wool 66 

Mercerizing,  chemicals  employed  in 318 

conditions  of 318 

contraction   of  cotton  during 323 

history  of 308 

machines  for 330 

methods  of 330 

quality  of  fibre  for 327 

quantity  of  caustic  sdoa  used  in 321 

temperature  for 3  20 

tension  in 324 

theory  of 317 

time  required  in 323 

use  of  sodium  chloride  in 319 

washing  as  a  process  in 326 

Mercerizing  liquors,  recovery  of  caustic  soda  from 332 

Merino  sheep 16,  23 

Meta-pectin ' 388 

Metal  threads 12 

Metallic  threads,  uses  of 13 

Metals  in  ash  of  weighted  silk,  testing  for 552 

Meteor  fabrics 373 

Methyl  value  of  fibres 179,  180 

Mexican  fibre 457 

Micro-analytical  tables  for  vegetable  fibres 494 

Microscopic  analysis  of  fabrics 574 

Microscopical  comparison  of  fibres 484 

Mildew,  varieties  of  on  cotton . 306 

Mildew  in  wool 74 

Milkweed  fibre 2,  347 

Millon's  reagent,  preparation  of 136 

Mineral  fibres : . 9 

Minor  hair  fibres 85 

Mirganji  jute ••••.•• 4°2 

Mississippi  cotton 211 

Mitafifi  cotton 218 

Mobile  cotton 211,  222 

Mohair 85 

microscopy  of 86 


618  INDEX 

PAGE 

Mohair  noils 87 

Moisture,  determination  of  in  vegetable  fibres 181 

influence  of  in  weaving  yarns 78 

Moisture  in  different  fibres 536 

fibres 77 

Monocotyledonous  plants 152 

Mordants 70 

Morocco-  sheep 16 

Morvant  de  la  chine 16 

Mountain  sheep 16 

[A  (mu),  meaning  of . ,   9 

Mulberry  silk,  analysis  of 133 

Mummy  cloths 382 

Mungo i 80 

Musa  paradisaica 157 

Muscardine  in  silkworm 115 

Mysore  sheep 16 


N 

Nankin  cotton 223 

Narainganji  jute ' 402 

Natural  silks,  microscopical  characteristics  of 495 

textures 161 

Nepal  sheep 16 

Nephila  Madagascar  iensis . 117 

Neri  silk 113 

Nesselgarn 452 

Nesseltuch 452 

Netting  fibres i6r 

Nettle  fibre 15?,  45* 

New  Zealand  flax i57>  43°>  5°6,  5°9 

distinction  from  jute,  hemp,  and  linen 476 

microscopy  of 433 

Nigretti  sheep ." 23 

Nitrated  cotton,  microscopy  of 290 

Nitration  value,  determination  of  in  vegetable  fibres 182 

Nitrates  of  cellulose 291 

Noils 45 

Non-Flam  process  of  flameproofing 3°4 

Norfolk  cotton 211 

Normal  cellulose 260 

preparation  of  from  cotton 270 

Nurma  cotton .  .                       207 


INDEX  619 


O 

PAGE 

Ochroma  lagopus 346,  502 

Oil  and  grease,  estimation  of  in  fabrics 568 

Oil  palm  fibre 157 

Okra  fibre 429 

Organzine  silk 1 28 

Orleans  cotton •'. 221 

Orsey  silk 129 

Onate  vegetale 346 

Oxycellulose ..,..,.. 290,  298 

tests  for 514 

Ovis  ammon 16 

ammon  guineensis 16 

aries 16 

dries  dngolensis 16 

dries  congensis , . . 16 

dries  numidifR . . . . 16 

dries  steatiniora 16 

barnal 16 

brevicaudatus 16 

Cdgid ...,,. 16 

ethiopiae 16 

guineensis . .. 16 

hispdnidl 16 

Idticduddtus 16 

longicaudatus 16 

musmon 16 

polyceratus 16 

rusticus 16 

selingid 16 

strepsiceros , . , ,, 16 


P 

Packing  fibre 164 

Pdind  limpa 343 

Palma  istle 450 

Panama  fibre 162 

hats,  fibre  for 162 

Pandanus  odoratissimus 156 

Pangane  hemp. 417,  452 

Paper  fibres .-   164,  166 

mulberry  fibre 157 

Para-pectin 388 

Parenchyma -. •j 


620  INDEX 

PAGE 

Pattes  de  lievre 346 

Pauly's  silk 360 

Peat  fibre 80 

Pebrine  in  silkworm 115 

Pectic  acid 388 

Pectin 388 

compounds  in  cotton , 264 

matters 388 

Pectinase 387 

Pectocelluloses 281 

Pectose 282,  388 

Pectosic  acid 388 

Peeler  cotton 211 

Penna  nobilis 1 50 

Perces  cocons 113 

Pernambuco  cotton 223 

Persian  wool 91 

Peruvian  cotton 222 

sea-island  cotton 217 

Phloe'm 154 

Phoenix  daclylifera 157 

Phormium  tenax 1 56,  430 

Piassave  fibre 174,  45$ 

Pigment  in  wool,  composition  of 40 

Pina  cloth 447 

Pineapple  fibre 157,  446,  504,  508 

Piques  cocoons 113 

Pita  fibre 156,  157,  444 

hemp .- 508,  509 

Plaiting  fibres 162 

Plant  cells '      6 

Plant  fibres,  anatomical  classification 153 

classification  of 153 

dimensions  of  raw 1 56 

Planta  de  Torquilla 162 

Pliability  of  textile  fibres 3 

Plumose  fibres 168 

Plush  goods,  analysis  of 523 

Poil  silk 130 

Polyvoltine  silkworms 107 

Poplar  cotton 498 

Porosity  of  fibres 4 

Properties  required  in  a  textile  fibre i 

Pseudo-fibres 159 

jute 505,  510 

Pua  hemp 417 

Pucha  sheep 16 


INDEX  621 

PAGE 

Pulled  wool 42 

Pulu  fibre 346 

Pure  cellulose,  isolation  of  in  vegetable  fibre 270 

hemp 418 

Pyroxene 9 

Pyroxylin 290 

hydrate 356 


Q 

Qualitative  tests  for  fibres 462 

Queensland  hemp 417 


R 

Rabbit-hair 103 

Ramie 157,  410,  503 

analysis  of 416 

Ramie  fibre,  microscopy  of 413 

yarns,  numbering  of 592 

Rangoon  hemp 41 7 

Raphia  fibre 454 

Raphia  taedigera 157 

vinifera 458 

Raw  silk,  microscopy  of  varieties  of 149 

weighting  of 553 

Reactions  of  natural  and  artificial  silks 486 

Reagents  for  testing  fibres 463 

Reed-mace  hair 498 

Regains  for  conditioning  textiles 534 

in  textiles,  mathematical  relations  in 541 

in  wool 76 

of  worsted  yarns 533 

Regenerated  cellulose 280 

Resist  colors 65 

dyeing 65 

Retting,  bacteria  of 387 

Retting  of  linen 382 

Rhea , • 410 

Ricotti  silk 113 

Rippling  flax 385 

Roa  fibre 503 

Roller  gin 197 

Roselle  hemp 417 

Rough  Peruvian  cotton 223 


622  INDEX 

PAGE 

Rugginose  cocoons 113 

Ruthenium  red,  microchemical  reagent 488 


S 

Sakusan  silk,  analysis  of 132 

Salix  alba . 157 

Sansevieria  fibre 157,  452,  507 

Santos  cotton 222 

Sarothamnus  mdgaris • 157 

Salurnia  cecropia 492 

polyphemus 492 

spini 491 

Savannah  cotton 211 

Saw  gin 197 

Schreiner  finish 342 

Schweitzer's  reagent,  preparation  of 269 

reactions  with 178 

Sclerenchymatous  fibres 1 70 

Scotch  method  of  sorting  wool .  . 19 

Scroop  of  silk 1 26 

on  mercerized  yarn 327 

on  wool 69 

Sea-grass 153,  454 

Sea-island  cotton »• 204,  215 

Sea-silk 150 

Sea-wrack 153 

Seed-fibres 153 

Seed-hairs 152,  168 

Selina  cotton 211 

Sericin 131,  138 

action  of  polarized  light  on  solution  of 140 

analysis  of • 138 

chemical  reactions  of 139 

preparation  of  pure 139 

Sericulture  in  America 106 

Serin 139 

Sewing  silk : 130 

numbering  of , 587 

Shaymbliar  sheep ....'. 16 

Sheep,  classes  of 16 

description  of 14 

first  mention  of  in  England 17 

varieties  of 16 

varieties  of  foreign  and  British 20 

Shoddy 79 


INDEX  623 

PAGE 

Shoddy,  analysis  of 523 

characteristics  of , 84 

detection  of 81 

in  fabrics 576 

examination  of 80 

method  of  carbonizing 80 

microscopy  of 80 

stripping  of  with  nitric  acid 64          . 

varieties  of 79 

Short-tailed  sheep 16 

Sida  retusa , 156 

Silk,  absorption  of  mixed  acids  by 63 

action  of  acids  on 141' 

action  of  Adamkiewitz's  reagent  on 136 

action  of  alcoholic  potash  on 136 

action  of  alkalies  on 143 

action  of  barium  hydrate  on 136 

action  of  chlorin  on 146 

action  of  dyestuffs  on 146 

action  of  formic  acid  on 146 

action  of  heat  on 141 

action  of  hydrochloric  acid  on 142 

action  of  hydrofluoric  acid  on 142 

action  of  hydrofluo-silicic  acid  on 142 

action  of  metallic  salts  on 143 

action  of  Millon's  reagent  on , 136, 

action  of  nitric  acid  on 141 

action  of  nitrous  acid  on 141 

action  of  polarized  light  on 493 

action  of  Schweitzer's  reagent  on 146 

action  of  sodium  chloride  on 144 

action  of  stannic  chloride  on 146 

action  of  sugar  on 146 

action  of  tannic  acid  on 141 

analysis  of 132 

ash  in t , 133 

biuret  test  for 137 

brightening  of 125 

chemical  constitution  of 131 

chemical  reactions  of , 141 

coefficient  of  acidity  of 61 

coloring  matter  of 140 

conditioning  of : 1 24 

density  of 1 26 

diazotizing  of 136 

electrical  potential  of 73 

electrical  properties  of 125 


624  INDEX 

PAGE 

Silk,  lustering  of I2$ 

lustre  of !  25 

microchemical  tests  for 490 

microscopical  characteristics  of  natural 495 

moisture  in j  24 

physical  properties  of 1 24 

production  of  crepon  effects  on , 143 

products  of  hydrolysis  from 137 

proportion  of  fibroin  in 135 

scroop  of ., j  26 

structure  of 105 

tensile  strength  of 125 

Silk  and  cotton  fabrics,  analysis  of 523 

Silk  cocoon,  formation  of 1 1 1 

Silk-cotton  plant , 214 

Silk  fabrics,  analysis  of  weighting  in 551 

Silk  fibre,  microchemical  reactions  of 1 20 

microscopy  of 1 20 

Silk  filament,  size  of 114 

thickness  of 114 

Silk-glue 131 

Silk-grass 157,  446 

Silk  industry,  history  of 106 

statistics  of 107 

Silk-reeling 127 

Silk  shoddy 113 

Silk  yarns,  numbering  of 583 

Silk-wadding 130 

Silkworm,  description  of 105 

diseases  of 114 

Silkworm  culture,  methods  of 107 

Silvalin  yarn 460 

Silver  cloth 347 

Simal  cotton 344 

Sinew  fibre 151 

Single  silk 130 

Sisal  hemp 439 

Size  of  yarns,  determination  of 577 

Slag  wool 13 

Small  hemp 417 

Smooth-haired  sheep 16 

Smooth  Peruvian  cotton 223 

Smyrna  cotton 218 

Sole  de  France 360 

Sole  ondee 130 

Soyan  cloth 119 

Spanish  sheep 16 


INDEX  625 

PAGE 

S  part  him  junceum 157 

Specific  heats  of  fibres 8 

Spider  silk 117 

Spinning  fibres 160 

Sponia  wight ii 156 

Spontaneous  combustion,  testing  fabrics  for 573 

Spun  glass,  fibres  from 12 

Spun  silk 1 28 

Spun  silk  yarns,  numbering  of , 587 

"  Staff,"  fibres  for 164 

Staple  of  wool 18 

Stearerin 51 

Stegmata  in  plant  fibres 1 76 

Stem-fibres 153,  166 

Stercnlia  villosa 156 

Sthenosage  process  for  artificial  silk 369 

Stripping  shoddy  with  nitric  acid 64 

Stripping  silk 131 

Strophantiis  fibre 500 

Structural  classification  of  vegetable  fibres 158 

Structural  fibres 158 

Strussa  silk 113 

Sugar-cane  hairs 498 

Suint 51 

Sulphur  dyes,  tendering  of  cotton  by 287 

Sultain  cotton 219 

Sunn  hemp 157,  425,  504,  512 

analysis  of 429 

Surat  cotton 221 

Surface  fibres 159 

Swedish  hemp '. 417 

Systematic  analysis  of  mixed  fibres 481 


T 

Tahiti  sea-island  cotton 217 

Talipot  palm  fibre 157 

Tampico  hemp 417 

Tanners'  wool 42 

Tannic  acid,  action  on  cotton 294 

Tarmate  cocoons 113 

Tartary  sheep 16 

Tensile  strength  of  fibres,  method  of  determining 253 

Texas  cotton .   211,  221 

Textile  fibres,  action  of  metallic  salts  on .- 71 

specific  gravity  of 555 


626  INDEX 

PAGE 

Textilose  yarns 459 

Theory  of  dyeing  of  cotton 304 

Thespesia  lampas 156 

Thibet  wool 80 

Thiele's  silk 363 

Thrown  silk,  numbering  of 587 

Tilia  europaea 157 

Tillandsia  fibre 156,  454 

usneoides 454 

Tin,  detection  of  in  textile  fabrics 558 

Titre  of  silk  yarns 583 

Tops 45 

Tow  yarns,  distinction  between  linen  and 393 

Tram  silk 128 

Tree-basts 161 

Tree  cotton 212 

True  Indian  hemp 425 

Tula  istle 450 

Tuscan  braid  fibres 162 

Tussah  silk 118,  147 

analysis  of T 133,  147 

analysis  of  ash  of 148 

comparison  of  with  true  silk 148 

structure  of 122,  149 

Tussur  silk 119 


U 

Unbarri  Egyptian  cotton 219 

Unripe  cotton,  properties  of 228 

Upholstery  fibres 163 

Upland  cotton 211,  221 

Urena  simiata 156,  452,  506 

Urtica  dioica 157,  451 

Urtica  nivea 157 

urena 451 

Uttariya  jute 401 


V 

Van  mohair 91 

Varieties  of  foreign  sheep 20 

Vascular  bundles J65 

fibres..                                                                    152 


INDEX  627 

PAGE 

Vasculose 282 

Vegetable  down 343,  498,  509 

Vegetable  fibres 6,  152 

analytical  reactions  of 471 

analytical  review  of 508 

chemical  composition  of 174 

chemical  constants  for 183 

chemical  investigation  of 180 

chemical  properties  of 174 

classification  of 157 

color  of 172 

determination  of  acid  purification  value  of 182 

determination  of  ash  in 181 

determination  of  carbon  percentage  in 182 

determination  of  cellulose  in 182 

determination  of  mercerizing  value  of. 182 

determination  of  moisture  in 181 

determination  of  nitration  value  of 182 

elasticity  of 172 

hydrolysis  of 181 

hygroscopic  properties  of 173 

lustre  of 172 

methyl  value  of 1 79 

physical  factors  of 412 

physical  properties  of 172 

physical  structure  of 168 

reactions  of  with  aniline  sulphate 179 

reactions  of  with  iodin-sulphuric  reagent 177 

reactions  of  with  polarized  light 171 

reactions  of- with  Schweitzer's  reagent 178 

statistics  of 160 

tensile  strength  of 173 

Vegetable  hairs 164 

Vegetable  horse-hair 454 

Vegetable  parchment 285 

Vegetable  silk 347,  498,  509,  510 

dimensions  of  fibre  of 156 

Vegetable  wool 350 

Vicogne 91 

Vicuna 91,  98 

Vicuna  wool 94 

Vine  cotton 218 

Viscolith 369 

Viscose 279,  298 

analysis  of 368 

determining  viscosity  of 368 

preparation  of . 364 


628  INDEX 

PAGE 

Viscose  silk 364 

Vulcanized  fibre 285 

W 

Wadding  silk 113 

Warp  silk 1 29 

Waste  silk,  boiling-off  of 128 

varieties  of 113 

Water  hemp 417 

Waterproof  quality  of  fabrics,  testing  the .  . 572 

Watt  silk 113 

Weft  silk ; 1 29 

Weighted  silk,  tendering  of 144 

tensile  strength  of 143 

Weighting  in  silk  fabrics,  estimation  of 551 

Weighting  on  silk,  calculation  of 564 

determination  of  by  Kjeldahl's  process.  .  . 560 

West  Indian  cottons 223 

West  Indian  sheep 16 

White  Egyptian  cotton 219,  221 

White  ramie  j 411 

Wild  hemp 417 

Wild  pineapple  fibre 157,  457 

Wild  silk,  distinction  of  from  true  silk 488 

microscopy  of : 122,  492 

varieties  of 1 16 

Wild  silkworms,  classification  of 1 18 

Willesden  canvas 284 

Willow  fibre •. 157 

Wood-wool 80 

Wood-pulp  yarns 459 

Woody  fibres 158 

Woody  fibre  in  vegetable  fibres 1 76 

Wool,  absorption  of  mixed  acids  by 63 

absorption  of  moisture  by 76 

absorption  of  sulphuric  acid  by 62 

acid  and  basic  nature  of 60 

acidified ; .  .  .  .  62 

action  of  acetyl  chloride  on 74 

action  of  acids  on 61 

action  of  alkalies  on 65 

action  of  alum  on 70 

action  of  chlorin  on 69 

action  of  chrome  on 71 

action  of  chromic  acid  on 63 

action  of  concentrated  caustic  soda  on .  .  66 


INDEX  629 

PAGE 

Wool,  action  of  concentrated  mineral  acids  on 65 

action  of  dilute  sulphuric  acid  on 62 

action  of  dyestuffs  on 72 

action  of  hydrochloric  acid  on 63 

action  of  hydrogen  peroxide  on 68 

action  of  metallic  salts  on 70 

action  of  milk  of  lime  on 67 

action  of  nitric  acid  on 63 

action  of  nitrous  acid  on 64 

action  of  organic  acids  on 65 

action  of  oxidizing  agents  on 67 

action  of  potassium  permanganate  on 68 

action  of  sodium  peroxide  on 68 

action  of  tannic  acid  on 65 

action  of  zinc  chloride  on 70 

chemical  analysis  of 49 

chemical  constitution  of ' 53 

chemical  nature  of 49 

chemical  reactions  of ;......  59 

chief  varieties  of 25 

coefficient  of  acidity  of 60 

coloring  matter  in 52 

comparative  number  of  scales  per  inch  on 37 

conditioning  of 76 

conditions  affecting  quality  of 46 

cortical  cells  in 38 

drying  of 76 

electrical  potential  of 73 

epidermal  scales  on - 31 

felting  quality  of ~. , 36 

hygroscopic  quality  of 75 

lustre  of _ 36 

medullary  cells  in 40 

method  of  carbonizing 80 

method  of  chlorinating 69,  90 

microchemical  reactions  of 75 

microscopy  of .' .  31 

mildew  on 74 

nature  of  scales  on ' 32 

nitrogen  in 55 

pedigree  of 17 

physiology  of 26 

pigment  matter  in 40 

production  of  scroop  on 69 

reaction  of  with  water 59 

size^of  epidermal  scales  on 37 

structure  of .  .  26 


630  INDEX 


Wool,  sulphur  in 57 

water  of  hydration  in 76 

yield  of  from  sheep 24 

Wool  and  cotton  fabrics,  analysis  of 517 

Wool  and  fur,  difference  between 15 

Wool  and  silk  fabrics,  analysis  of 522 

Wool-bearing  animals 15 

Wool-fat,  purpose  of . 27 

Wool  fibre,  ash  of 51 

diameter  of 45 

elasticity  of ' 44 

general  textile  properties  of 14 

length  of 45 

physical  properties  of 43 

pliability  of : 38 

removal  of  waviness  in 39 

tensile  strength  of 44 

waviness  of 38 

Wool-grading 18 

Wool  grease 50 

Wool-hair 18 

Wool  oil 50 

Wool-sorter's  disease 91 

Wool-sorting '.  .  .  18 

Wool  substitutes 79 

Woolen  materials,  imports  of  into  U.  S 24 

Woolen  yarns 46 

numbering  of 582 

Worsted  yarns !" 45 

comparative  strength  of 45 

numbering  of 582 

X 

Xanthoproteic  acid 142 

from  wool 63 

Xylem 154 

Xylolin  yarns 459 

Y 

Yama-mai  silk,  analysis  of 132 

Yannovitch  cotton 218 

Yenu  sheep 16 

Yucca  fibre 157,  508 

Z 

Zeylan  sheep 16 

Zostera  marina 153,  454 


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GERHARD — Guide  to  Sanitary  Inspections 12mo,  1  50 

Modern  Baths  and  Bath  Houses .Svo,  *3  00 

Sanitation  of  Public  Buildings 12mo,      1   50 

The  Water  Supply,  Sewerage,  and  Plumbing  of  Modern  City  Buildings. 

Svo,  *4  00 

H AZEN — Clean  Water  and  How  to  Get  It Small  Svo,  1  50 

Filtration  of  Public  Water-supplies Svo,  3  00 

KIXNICUTT,  WINSLOW  and  PRATT — Sewage  Disposal Svo,  *3  00 

LEACH — Inspection  and  Analysis  of  Food  with  Special  Reference  to  State 

Control Svo,  7  50 

MASON — Examination  of  Water.     (Chemical  and  Bacteriological.)..  .  .12mo,  1  25 

Water-supply.     (Considered  principally  from  a  Sanitary  Standpoint.) 

•                                                Svo,  4  00 

MERRIMAN — Elements  of  Sanitary  Engineering Svo,  *2  00 

OGDEN — Sewer  Construction Svo,  3  00 

Sewer  Design 12mo,  2  00 

OGDEN  and   CLEVELAND — Practical   Methods  of  Sewage  Disposal  for  Res- 
idences, Hotels  and  Institutions Svo,  *1  50 

PARSONS — Disposal  of  Municipal  Refuse Svo,  2  00 

19 


PRESCOTT  and  WINSLOW — Elements  of  Water  Bacteriology,   with  Special 

Reference  to  Sanitary  Water  Analysis 12mo,   $1  50 

PRICE — Handbook  on  Sanitation 12mo,  *1  50 

RICHARDS — Conservation  by  Sanitation 8vo,     2  50 

Cost  of  Cleanness 12mo,     1  00 

Cost  of  Food.     A  Study  in  Dietaries 12mo,     1  00 

Cost  of  Living  as  Modified  by  Sanitary  Science 12mo,      1  00 

Cost  of  Shelter 12mo,      1  00 

Laboratory  Notes  on  Industrial  Water  Analysis 8vo,  *0  50 

RICHARDS  and  WOODMAN — Air,  Water,  and  Food  from  a  Sanitary  Stand- 
point   ' 8vo,     2  00 

RiCHEY — Plumbers',  Steam-fitters',  and  Tinners'  Edition  (Building  Mechan- 
ics' Ready  Reference  Series) 16mo,  mor.,  *1  50 

RIDEAL — Disinfection  and  the  Preservation  of  Food 8vo,     4  00 

SOPER — Air  and  Ventilation  of  Subways 12mo,     2  50 

TURNEAURE  and  RUSSELL — Public  Water-supplies 8vo,     5  00 

VENABLE — Garbage  Crematories  in  America 8vo,     2  00 

Method  and  Devices  for  Bacterial  Treatment  of  Sewage 8vo,     3  00 

WARD  and  WHIPPLE — Freshwater  Biology (In  Press.) 

WHIPPLE — Microscopy  of  Drinking-water 8vo,     3  50 

Typhoid  Fever Small  8vo,  *3  00 

Value  of  Pure  Water Small  8vo,     1  00 


MISCELLANEOUS. 

BuRT — Railway  Station  Service 12mo,  *2  00 

CHAPIN — How  to  Enamel 12mo,  *1  00 

EMMONS — Geological  Guide-book  of  the  Rocky  Mountain  Excursion  of  the 

International  Congress  of  Geologists Large  8vo,      1   50 

FERREL — Popular  Treatise  on  the  Winds 8vo,     4  00 

FITZGERALD — Boston  Machinist 18mo,     1  00 

FRITZ — Autobiography  of  John 8vo,  *2  00 

GANNETT — Statistical  Abstract  of  the  World 24mo,     0  75 

GREEN — Elementary  Hebrew  Grammar 12mo,     1  25 

HAINES — American  Railway  Management 12mo,     2  50 

HANAUSEK — The  Microscopy  of  Technical  Products.      (WiNTON.) 8vo,     5  00 

JACOBS — Betterment  Briefs.     A  Collection  of  Published  Papers  on  Organ- 
ized Industrial  Efficiency 8vo,     3  50 

METCALFE — Cost  of  Manufactures,  and  the  Administration  of  Workshops. 

8vo,     5  00 

PARKHURST — Applied  Methods  of  Scientific  Management 8vo,  *2  00 

PUTNAM — Nautical  Charts 8vo,     2  00 

RICKETTS — History  of  Rensselaer  Polytechnic  Institute,  1824-1894. 

Small  8vo,     3  00 
ROTCH  and  PALMER — Charts  of  the  Atmosphere  for  Aeronauts  and  Aviators. 

Oblong  4to,  *2  00 

ROTHERHAM — Emphasised  New  Testament Large  8vo,     2  00 

RUST — Ex- Meridian  Altitude,  Azimuth  and  Star-finding  Tables 8vo,     5  00 

STANDAGE — Decoration  of  Wood,  Glass,  Metal,  etc 12mo,     2  00 

WESTERMAIER — Compendium  of  General  Botany.     (SCHNEIDER.) 8vo,     2  00 

WINSLOW — Elements  of  Applied  Microscopy 12mo,     1  50 


20 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
This  book  is  DUE  on  the  last  date  stamped  below 
Fine1"  •*  — '• 


10  1947 
DEC  16  1947 


One  dollar  on  seventh  day-overdue. 

~  --  1  -  -  -  ' 

REC'D  LD  30Mar58MF 

OCT  10  1956 

SNov'6608 
REC  D  LD 


OCT  29  1356 

24lan"57GC 
REC'D  LD 

17  195' 


REC'D  LD 

SEP  2  5  1956 

MAR13J958 

LD  21-100M-12,'46(A2012sl6)4120 


°JAf|2~Mtf'5SCi 
3  LD 


LD 


Me 


261189 


